Abstract
Background
Intra-aortic balloon pumps (IABPs) have been employed to stabilize patients with acute-on-chronic cardiogenic shock. The use of IABP to optimize patients for successful left ventricular assist device (LVAD) implantation has not been well-studied.
Methods
This is a single-center retrospective cohort of adults (>18 years) undergoing durable LVAD implantation between April 2011 and June 2019. One-to-one propensity matching paired patients requiring preoperative IABP placement with those who did not. The primary outcome assessed was 1-year mortality, with secondary outcomes, including hospital and intensive care unit (ICU), length of stay (LOS), duration of mechanical ventilation, and complications. Further analysis examined postoperative changes in systolic pulmonary artery pressure (PAP), cardiac index (CI), and pulmonary capillary wedge pressure (PCWP).
Results
Among 189 patients, preoperative IABP was used in 53 patients (28.0%). Of these, 32 patients were matched to 32 patients not requiring preoperative IABP placement. One-year mortality was not significantly different between IABP and non-IABP groups (17.0 vs 12.5%, p = 0.422). After matching, there were no significant differences in hospital LOS, ICU LOS, hours of postoperative mechanical ventilation, or complications including stroke, requirement for new renal replacement therapy, right heart failure, hemorrhagic complication, or infection requiring antibiotics. From the time of admission to within 24 hours prior to LVAD implantation, patients supported with IABP had greater reductions in systolic PAP and PCWP, and larger increases in CI.
Conclusions
In our study, patients requiring IABP support for stabilization undergoing durable LVAD implant had similar 1-year survival to those not requiring IABP support. Patients supported on IABP had larger reductions in PCWP and sPAP with greater increases in CI prior to LVAD implant.
Keywords: LVAD, heart failure, optimization, IABP, mechanical circulatory support
The use of durable left ventricular assist devices (LVADs) as long-term destination therapy has increased from about 50% of all LVAD patients in 2018 to over 70% of all LVAD patients in 2019 since the new US heart allocation system was introduced.1 Improvements in LVAD technology and management have led to 1-year survival rates of 84–85%2; yet, adverse events such as right heart failure remain common following LVAD implantation. Although difficult to accurately capture due to the lack of a universal definition, up to 44% of patients develop right ventricular failure postoperatively.3, 4 This postoperative complication of LVAD implantation is associated with higher morbidity and mortality,5 and although risk factors have been identified, it remains difficult to identify patients who will develop right ventricular failure.6 The use of an intra-aortic balloon pump (IABP) preoperatively in high-risk patients has been proposed as a solution to optimize high-risk candidates prior to LVAD implantation.
Few studies evaluate and compare adult LVAD patients supported with IABP preoperatively versus those who were not. An evaluation of the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) evaluated 2,446 patients, 433 (18%) of which were supported with IABP preoperatively, and found that patients supported with IABP preoperatively had markers of more advanced disease at baseline but no difference in the composite outcome of post-LVAD right heart failure, hepatic dysfunction, renal dysfunction, or death.7 However, institutional studies allow for examination of site-level variation that is not possible using INTERMACS data. The largest institutional study of matched patients included 22 patients supported with IABP before LVAD and 22 patients not supported with IABP.8 Imamura and colleagues8 evaluated patients undergoing LVAD between 2007 and 2014 and found that the IABP group had shorter postoperative intensive care unit (ICU) stay and more improved hemodynamics with no difference in 1-year survival. Contemporary, propensity-matched institutional studies evaluating comprehensive clinical outcomes of preoperative IABP optimization in LVAD patients are lacking.
The purpose of this study is to review our contemporary single institutional experience of adult patients undergoing LVAD implantation over an 8-year period (April 2011 through June 2019) to compare baseline characteristics, clinical outcomes, and hemodynamic changes among patients supported with preoperative IABP versus propensity-matched patients who were not supported with temporary MCS prior to LVAD implantation. We hypothesized that preoperative IABP use before LVAD implantation could be used as an optimization strategy to yield similar or improved mid-term outcomes in patients presenting with more advanced heart failure.
Material and methods
Study design and population
We performed a single-center, retrospective cohort study of all adults (>18 years of age) who underwent LVAD implantation between April 2011 and June 2019. Patients who underwent preoperative percutaneous ventricular support device implantation, preoperative extracorporeal membrane oxygenation (ECMO), or prior LVAD implantation requiring exchange were excluded. This study was approved by the University of Florida Institutional Review Board with waiver of the need for patient informed consent.
Data collection and outcomes
Data were obtained from a prospectively maintained database and from electronic medical records. Preoperative data recorded included age, race, sex, body mass index (BMI), past medical history, and indication for LVAD therapy (bridge to transplant [BTT] or destination therapy [DT]). Postoperative data included hospital and ICU length of stay, duration of ventilator support, complications, and mortality.
Hemodynamic and echocardiographic data were also recorded before IABP placement and the first day after LVAD implantation. Hemodynamic data recorded included cardiac index (CI) (liter/min/m2), right atrial (RA) pressure (mm Hg), systolic pulmonary artery pressure (PAP) (mm Hg), pulmonary artery pulsatility index (PAPi), and pulmonary capillary wedge pressure (PCWP) (mm Hg). Echocardiographic data included ejection fraction (EF) (%), left ventricular end diastolic dimension (LVEDD) (cm) and left ventricular end systolic dimension (LVESD) (cm). Vasoactive-inotropic score (VIS) was calculated preoperatively within 24 hours prior to LVAD implantation.
In the survival analyses, the primary outcome was all-cause mortality. Right heart failure was defined according to the INTERMACS.9 Cerebrovascular accident (CVA) was defined as a new neurological deficit associated with ischemic or hemorrhagic neuroimaging findings. A hemorrhagic event was defined as a gastrointestinal (GI) bleeding event. Gastrointestinal bleeding was defined as hematemesis, melena, or active bleeding on endoscopy or colonoscopy. Infection encompasses driveline infections, pump infections, and any source of sepsis.
Statistical analysis
Data are presented before and after propensity matching. Continuous variables are presented as median [25th percentile, 75th percentile] (range), and categorical variables are presented as n (%). Mann-Whitney test was used for continuous variables; Chi square and Fisher’s exact tests were used for categorical variables. The R package, MatchIt, was used to match preoperative IABP patients with patients not supported with IABP who were most similar in sex, age, race, BMI, New York Heart Association (NYHA), INTERMACS profile, type of cardiomyopathy (ischemic vs non-ischemic), indication, obesity, hypertension, hyperlipidemia, diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD), pulmonary hypertension (PHT), chronic kidney disease (CKD), coronary artery disease (CAD), cerebrovascular disease (CVD), prior cardiac surgery and need for preoperative ventilation. Missing data was imputed with the mode before matching. Matching, performed at a standard caliper width of 0.2 (caliper width = #standard deviations of the propensity score), resulted in 32 matched pairs. In matched data, the estimated effect of IABP (vs no IABP) on outcomes was estimated with logistic or linear regression. For all confidence intervals and p-values, a cluster-robust variance, as implemented in the vcovCL() function in the R Sandwich package was used to estimate standard errors with the matched pair as the clustering variable. All statistical analyses were performed in R Statistical Software (Vienna, Austria). A p-value <0.05 was considered statistically significant.
Results
Demographics and baseline characteristics
During the study period, 189 patients met inclusion criteria. Of these, 53 patients (28.0%) underwent IABP placement before an LVAD was implanted. Almost all patients were supported with femoral IABP (98.1%, n = 52), while the remaining patients were supported with axillary IABP. Our protocols include ambulation for patients with axillary IABP, while ambulation is limited in patients with femoral IABP due to risk of kinking. IABP was initiated for stabilization rather than optimization in 48 of 53 (90.6%) patients. Mean duration of IABP use was 7.74 ± 5.69 days. IABP removal occurred before LVAD implantation in most patients (44.9%, n = 22). For the 13 patients who had the IABP removed post-LVAD implant, all IABPs were removed on day 1 following LVAD implantation, before obtaining hemodynamic measurements. IABP complications occurred in 28 (52.8%) patients and included hematoma (26.4%, n = 14) and infection (7.5%, n = 4). LVAD type amongst patients did not vary with 67.9% (n = 36) versus of 61.0% (n = 83) supported with Heartmate II (p = 0.378), 15.1% (n = 8) versus of 20.6% (n = 28) supported with Heartmate III (p = 0.536), and 17.0% (n = 9) versus of 18.4% (n = 25) supported with Heartware (p = 0.999), across IABP and no IABP groups respectively.
Propensity matching resulted in 32 matched pairs. Demographic characteristics of unmatched and matched patients are shown in Table 1 and Table 2, respectively. Given the study period, most patients were supported with HeartMate II (63.0%, n = 119), and there were no differences in LVAD support device between groups. Overall, compared to the non-IABP group, the IABP group was younger (median [IQR]: 54 [46,62] vs 62 [50,68] days, p = 0.003) and had a higher proportion of Black patients (49.1 vs 24.3%, p = 0.023), lower median BMI (median [IQR]: 27.2 [24,31] vs 29.4 [25,34] kg/m2, p = 0.012), more patients requiring preoperative mechanical ventilation (22.2 vs 2.9%, p < 0.0001), and a higher percentage of patients in worse INTERMACS profiles (91.6 vs 53.0% INTERMACS I or II, p < 0.0001). Matching eliminated these differences to allow for a balanced outcomes analysis. However, device type, specifically with regards to the Heartmate II and Heartware varied between matched cohorts with 78.1% (n = 25) versus of 40.6% (n = 13) supported with Heartmate II (p = 0.002) and 9.4% (n = 3) versus of 34.4% (n = 11) supported with Heartware (p = 0.032), across IABP and no IABP groups respectively.
Table 1.
Unmatched Patient and Procedural Characteristics by IABP Status
| Overall (N = 189) | No IABP (N = 136, 71.2%) | IABP (N = 53, 28.8%) | p | N (%) Missing | |
|---|---|---|---|---|---|
| Male | 151 (79.9) | 108 (79.4) | 43 (81.1) | 0.791 | 0 |
| Age (years) | 59 [48,67] (20,79) | 62 [50,68] (22,79) | 54 [46,62] (20,70) | 0.003 | 0 |
| Race | |||||
| White | 117 (61.9) | 91 (66.9) | 26 (49.1) | 0.023 | 0 |
| Black | 59 (31.2) | 33 (24.3) | 26 (49.1) | ||
| Other | 13 (6.9) | 12 (8.8) | 1 (1.8) | ||
| BMI (kg/m2) | 28.6 [25,34] (18,49) | 29.4 [25,34] (18,49) | 27.2 [24,31] (18,38) | 0.012 | 0 |
| NYHA Classification III (vs IV) | 19 (10.3) | 17 (12.9) | 2 (4.0) | 0.002 | 7 (3.7) |
| INTERMACS scale (%) III-V (vs I-II) | 67 (36.6) | 62 (47.0) | 5 (8.4) | <0.0001 | 8 (4.2) |
| Ischemic cardiomyopathy | 70 (38.1) | 53 (39.0) | 17 (32.1) | 0.378 | 0 |
| Indication= BTT (vs DT) | 71 (37.0) | 44 (32.3) | 26 (49.1) | 0.033 | 0 |
| Obese | 47 (24.9) | 41 (30.1) | 6 (11.3) | 0.008 | 0 |
| HTN | 125 (66.1) | 96 (70.6) | 29 (55.8) | 0.038 | 1 (0.5) |
| Hyperlipidemia | 86 (46.5) | 62 (46.3) | 24 (47.1) | 1 | 4 (2.1) |
| DM | 75 (39.7) | 58 (42.6) | 17 (33.3) | 0.182 | 2 |
| COPD | 22 (11.6) | 19 (14.1) | 3 (5.8) | 0.133 | 2 (1.0) |
| Pulmonary artery hypertension | 75 (39.7) | 51 (37.5) | 24 (45.3) | 0.326 | 0 |
| CKD | 97 (51.3) | 70 (51.5) | 27 (51.9) | 0.948 | 1 (0.5) |
| CAD | 98 (51.9) | 75 (55.6) | 23 (44.2) | 0.146 | 2 (1.0) |
| CVA | 21 (11.1) | 18 (13.3) | 3 (5.8) | 0.198 | 2 (1.0) |
| Prior cardiac surgery | 53 (28.0) | 46 (34.1) | 7 (13.2) | 0.004 | 1 (0.5) |
| Preop ventilation | 16 (8.5) | 4 (2.9) | 12 (22.2) | <0.0001 | 1 (0.5) |
| Indication for IABP implant = stabilization (vs optimization) | 48 | - | 48 (90.6) | - | 0 |
| LVAD type | |||||
| Heartmate II | 119 (63.0) | 83 (61.0) | 36 (67.9) | 0.378 | |
| Heartmate III | 36 (19.0) | 28 (20.6) | 8 (15.1) | 0.536 | |
| Heartware | 34 (18.0) | 25 (18.4) | 9 (17.0) | 0.999 | |
| IABP removal | - | 4 (2.1) | |||
| Before LVAD | 22 (11.6) | - | 22 (44.9) | - | |
| In the OR | 14 (7.4) | - | 14 (28.6) | - | |
| After LVAD | 13 (6.9) | - | 13 (26.5) | - | |
| IABP complications | 28 (14.8) | 28 (52.8) | 0 | ||
| Hematoma | 14 (7.4) | - | 14 (26.4) | - | |
| Infection | 4 (2.1) | - | 4 (7.5) | - | |
| Dissection | 0 (0) | - | 0 (0) | - | |
| Kinking | 0 (0) | - | 0 (0) | - | |
| IABP access = Femoral (vs axillary) | 52 (27.5) | - | 52 (98.1) | - | 0 |
BMI, body mass index; BTT, bridge to transplant; CAD, coronary artery disease; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular accident; DM, diabetes mellitus; DT, destination therapy; HTN, hypertension; IABP, intra-aortic balloon pump; INTERMACS, Interagency Registry for Mechanically Assisted Circulatory Support; NYHA, New York Heart Association; Preop, preoperative.
Values are presented as N (%) or median [interquartile range] (range).
Table 2.
Matched Patient and Procedural Characteristics by IABP Status
| No IABP (N = 32, 50%) | IABP (N = 32, 50%) | p | |
|---|---|---|---|
| Male | 28 (87.5) | 28 (87.5) | 1 |
| Age (years) | 59 [46,65] (30,76) | 57 [48,62] (36,69) | 0.957 |
| Race | |||
| White | 22 (68.8) | 20 (62.5) | 0.599 |
| Black | 10 (31.2) | 12 (37.5) | |
| Other | 0 (0) | 0 (0) | |
| BMI (kg/m2) | 29.8 [25,35] (18,42) | 27.8 [25,32] (22,38) | 0.293 |
| NYHA classification III (vs IV) | 0 (0) | 1 (3.1) | (N/A) |
| INTERMACS scale (%) III-V (vs I-II) | 4 (12.5) | 5 (15.6) | 1 |
| Ischemic cardiomyopathy | 11 (34.4) | 10 (31.3) | 0.790 |
| Indication = BTT (vs DT) | 13 (40.6) | 14 (43.8) | 0.800 |
| Obese | 7 (21.9) | 5 (15.6) | 0.750 |
| HTN | 19 (59.4) | 19 (59.4) | 1 |
| Hyperlipidemia | 14 (43.8) | 15 (46.9) | 0.802 |
| DM | 10 (31.3) | 11 (34.4) | 0.790 |
| COPD | 3 (9.4) | 3 (9.4) | 1 |
| Pulmonary artery hypertension | 17 (53.1) | 18 (56.3) | 0.802 |
| CKD | 18 (56.2) | 18 (56.2) | 1 |
| CAD | 14 (43.8) | 15 (46.9) | 0.802 |
| CVA | 0 (0) | 2 (5.6) | N/A |
| Prior cardiac surgery | 7 (36.1) | 6 (27.8) | 1 |
| Preop ventilation | 3 (9.4) | 1 (3.1) | 0.613 |
| LVAD type | |||
| Heartmate II | 13 (40.6) | 25 (78.1) | 0.002 |
| Heartmate III | 8 (25.0) | 4 (12.5) | 0.337 |
| Heartware | 11 (34.4) | 3 (9.38) | 0.032 |
BMI, body mass index; BTT, bridge to transplant; CAD, coronary artery disease; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular accident; DM, diabetes mellitus; DT, destination therapy; HTN, hypertension; IABP, intra-aortic balloon pump; INTERMACS, Interagency Registry for Mechanically Assisted Circulatory Support; NYHA, New York Heart Association; Preop, preoperative.
Values are presented as N (%) or median [interquartile range] (range).
Preoperative hemodynamics, laboratory data, and echocardiographic findings
Preoperative hemodynamic parameters, laboratory data, and echocardiographic findings indicating severity of shock are displayed in Table 3 (unmatched) and Table 4 (matched). Patients supported with IABP preoperatively had higher preoperative RA pressure (median [IQR]: 17 [13,22] vs 11 [8,15] mm Hg, p < 0.0001) and PCWP (median [IQR]: 32 [25,40] vs 25 [19,30] mm Hg, p < 0.0001), and lower preoperative CI (median [IQR]: 1.5 [1.3, 1.8] vs 1.7 [1.5, 2.1] liter/min/m2, p = 0.065). These patients also had lower preoperative hemoglobin (median [IQR]: 11.3 [9.8,12.2] vs 11.9 [10.7,13.1] g/dl, p = 0.048) and higher preoperative white blood cell count (median [IQR]: 7.9 [6.9,9.6] vs 6.7 [5.6,8.3] 103/µl, p = 0.004), total bilirubin (median [IQR]: 1.1 [0.7,1.6] vs 0.7 [0.5,1.1] mg/dl, p = 0.009), and alanine aminotransferase (median [IQR]: 31 [22,59] vs 21 [15,35] U/liter, p = 0.002). No significant differences were observed in echocardiographic findings including ejection fraction, LVEDD, and LVESD. VIS score, calculated within 24 hours prior to LVAD implantation, was similar between IABP and non-IABP patients (median [IQR]: 5.97 [3.75,8] vs 3.75 [1.81, 5.0], p = 0.430). Before matching, there was no difference in admission PAPi between groups. However, after matching for other characteristics, patients supported with IABP had lower admission PAPi (median [IQR]: 1.9 [1.8,2.7] vs 2.5 [2.3,5.4], p = 0.013). Preoperative differences in RA pressure, PCWP, and CI persisted after matching.
Table 3.
Unmatched Preoperative Hemodynamics, Laboratory Data, and Echocardiographic Findings
| Overall (N = 189) | No IABP (N = 136, 71.2%) | IABP (N = 53, 28.8%) | p | N (%) missing | |
|---|---|---|---|---|---|
| Preop HR | 80 [71,92] (53,125) | 78 [71,91] (54,123) | 83 [72,94] (53,125) | 0.069 | 6 (3.1) |
| Preop systolic BP (mm Hg) | 103 [95,111] (76,151) | 102 [95,111] (81,151) | 105 [96,114] (76,135) | 0.433 | 2 (1.0) |
| Preop RA Pressure (mm Hg) | 13 [8,17] (2,35) | 11 [8,15] (2,25) | 17 [13,22] (2,35) | <0.0001 | 1 (0.5) |
| Preop PCWP (mm Hg) | 27 [20,33] (6,62) | 25 [19,30] (6,48) | 32 [25,40] (10,62) | <0.0001 | 0 |
| Preop CI (liter/min/m2) | 1.7 [1.4,2.0] (0.7,15) | 1.7 [1.5,2.1] (0.9,15) | 1.5 [1.3,1.8] (0.7,2.4) | 0.065 | 22 (11.5) |
| Preop EF (%) | 15 [10,20] (5,35) | 15 [10,20] (5,35) | 10 [10,15] (5,35) | 0.216 | 18 (9.4) |
| Preop LVEDD (cm) | 6.9 [6.1,7.6] (4.9,10.4) | 6.9 [6.0,7.6] (4.9,10.4) | 7.1 [6.4,7.7] (5.3,10.2) | 0.154 | 18 (9.4) |
| Preop LVESD (cm) | 6.3 [5.5,7.0] (3.7,20.0) | 6.3 [5.4,6.9] (3.7,20) | 6.5 [5.8,7.1] (4.6,9.8) | 0.543 | 20 (10.5) |
| Preop creatinine (mg/dl) | 1.2 [1.0,1.6] (0.4,4.0) | 1.2 [1.1,1.6] (0.4,3.8) | 1.2 [1.0,1.5] (0.6,4.0) | 0.292 | 0 |
| Preop BUN (mg/dl) | 24 [18,34] (5,154) | 24 [20,33] (5,154) | 24 [17,38] (6,90) | 0.336 | 0 |
| Preop Hb (g/dl) | 11.6 [10.5,13.0] (7.4,45) | 11.9 [10.7,13.1] (7.4,45) | 11.3 [9.8,12.2] (7.7,16.3) | 0.048 | 0 |
| Preop WBC (103/µl) | 7.3 [5.7,9.0] (2.8,20.5) | 6.7 [5.6,8.3] (2.8,17.2) | 7.9 [6.9,9.6] (3.3,20.5) | 0.004 | 1 (0.5) |
| Preop Plt (103/µl) | 195 [160,262] (63,578) | 198 [166,262] (63,578) | 194 [150,252] (67,419) | 0.445 | 1 (0.5) |
| Preop total bilirubin (mg/dl) | 0.8 [0.5,1.2] (0.1,13.6) | 0.7 [0.5,1.1] (0.1,5.1) | 1.1 [0.7,1.6] (0.2,13.6) | 0.009 | 9 (4.7) |
| Preop ALT (U/liter) | 24 [17,39] (6,698) | 21 [15,35] (6,258) | 31 [22,59] (6,698) | 0.002 | 9 (4.7) |
| VIS Score | 4 [2.5,6.8] (0,413) | 3.75 [1.81,5.0] (0,413) | 5.97 [3.75, 8] (0,408) | 0.430 | 0 |
ALT, alanine aminotransferase; BP, blood pressure; BUN, blood urea nitrogen; CI, confidence interval; EF, ejection fraction; Hb, hemoglobin; HR, heart rate; IABP, intra-aortic balloon pump; LVEDD, left ventricular end diastolic dimension; LVESD, left ventricular end systolic dimension; PCWP, pulmonary capillary wedge pressure; Plt, platelet; Preop, preoperative; RA, right atrial; WBC, white blood cell.
Values are presented as median [interquartile range] (range).
Table 4.
Matched Preoperative Hemodynamics, Laboratory Data, and Echocardiographic Findings
| No IABP (N = 32, 50%) | IABP (N = 32, 50%) | p | |
|---|---|---|---|
| Preop HR | 78.5 [73,92] (60,109) | 78 [70,89] (53,109) | 0.651 |
| Preop systolic BP (mm Hg) | 99 [94,107] (81,143) | 108 [101,115] (84,135) | 0.096 |
| Preop RA Pressure (mm Hg) | 11 [9,15] (2,22) | 18 [14,22] (5,35) | 0.0001 |
| Preop PCWP (mm Hg) | 25 [22,30] (6,40) | 35 [27,40] (17,62) | <0.0001 |
| Preop CI (liter/min/m2) | 1.7 [1.5,2.0] (1.1,2.9) | 1.4 [1.2,1.7] (0.7,2.4) | 0.014 |
| Preop EF (%) | 10 [10,15] (10,25) | 10 [10,19] (10,35) | 0.281 |
| Preop LVEDD (cm) | 5.6 [5.1,6.8] (3.4,9.3) | 5.9 [5.4,76.3] (3.3,7.1) | 0.426 |
| Preop LVESD (cm) | 5 [4.4,6.3] (3.2,9.3) | 5.3 [4.7,5.9] (3.1,6.9) | 0.424 |
| Preop creatinine (mg/dl) | 1.3 [1.1,1.5] (0.4,2.2) | 1.3 [1.0,1.5] (0.6,2.3) | 0.927 |
| Preop BUN (mg/dl) | 26 [20,37] (12,64) | 23 [18,35] (12,86) | 0.954 |
| Preop Hb (g/dl) | 11.9 [10.7,13.3] (7.4,45) | 11.5 [10.0,12.6] (8.1,16.3) | 0.172 |
| Preop WBC (103/µl) | 6.4 [5.2,8.6] (2.8,12.3) | 7.7 [6.7,9.5] (3.3,11.5) | 0.109 |
| Preop Plt (103/µl) | 196.5 [170,264] (63,447) | 178 [151,246] (72,360) | 0.311 |
| Preop total bilirubin (mg/dl) | 0.9 [0.6,1.2] (0.2,2.3) | 0.9 [0.5,1.3] (0.2,4.0) | 0.574 |
| Preop ALT (U/liter) | 20.5 [15,30] (11,255) | 27 [19,35] (6,698) | 0.226 |
| VIS Score | 5.0 [2.8, 5.6] (0,15.0) | 5.0 [3.4, 7.5] (0,50.1) | 0.155 |
ALT, alanine aminotransferase; BP, blood pressure; BUN, blood urea nitrogen; CI, confidence interval; EF, ejection fraction; Hb, hemoglobin; HR, heart rate; IABP, intra-aortic balloon pump; LVEDD, left ventricular end diastolic dimension; LVESD, left ventricular end systolic dimension; PCWP, pulmonary capillary wedge pressure; Plt, platelet; Preop, preoperative; RA, right atrial; WBC, white blood cell.
Values are presented as median [interquartile range] (range).
Postoperative clinical outcomes and survival analysis
Postoperative clinical outcomes for unmatched and matched patients are shown in Table 5 and Table 6, respectively. Propensity-matched outcome analysis includes the estimated effect of IABP (vs no IABP) on each outcome. Before matching, patients supported with preoperative IABP had longer hospital and ICU LOS (median [IQR]: 41 [30,52] vs 25 [19,39] days, p = 0.0006; 11 [8,18] vs 8 [7,13] days, p = 0.057; respectively) and a higher rate of right heart failure (58.5 vs 42.6%, p = 0.050). Propensity matching revealed no differences in any postoperative outcomes measured or in survival through 1 year.
Table 5.
Unmatched Postoperative Clinical Outcomes and Survival
| Overall (N = 189) | No IABP (N = 136, 71.2%) | IABP (N = 53, 28.8%) | p | N (%) missing | |
|---|---|---|---|---|---|
| Hospital LOS (days) | 30 [21,45] (11,196) | 25 [19,39] (11,196) | 41 [30,52] (15,140) | 0.0006 | 0 |
| ICU LOS (days) | 9 [7,14] (3,112) | 8 [7,13] (3,104) | 11 [8,18] (5,112) | 0.057 | 1 (0.5) |
| Mechanical Ventilation (hours) | 24 [20,45] (7,1020) | 24 [19,44] (7,1020) | 25 [22,45] (12,384) | 0.723 | 5 (2.6) |
| Respiratory complication | 50 (26.5) | 38 (27.9) | 12 (22.6) | 0.458 | 0 |
| Right heart failure | 89 (47.1) | 58 (42.6) | 31 (58.5) | 0.050 | 0 |
| CVA | 7 (3.7) | 7 (5.1) | 0 (0) | NA | 0 |
| Infection | 43 (22.8) | 29 (21.3) | 14 (26.4) | 0.453 | 0 |
| Hemorrhagic event | 36 (19.0) | 25 (18.4) | 11 (20.7) | 0.709 | 0 |
| Dialysis | 20 (10.6) | 12 (8.9) | 8 (15.1) | 0.291 | 4 (2.1) |
| Heart transplant | 37 (19.6) | 24 (17.6) | 13 (24.5) | 0.284 | 0 |
| 1-month mortality | 3 (1.6) | 2 (1.5) | 1 (1.9) | 0.837 | 0 |
| 6-month mortality | 18 (9.5) | 13 (9.5) | 5 (9.4) | 0.979 | 0 (0) |
| 12-month mortality | 26 (13.8) | 17 (12.5) | 9 (17.0) | 0.422 | 13 (6.8) |
CVA, cerebrovascular accident; IABP, intra-aortic balloon pump; ICU, intensive care unit; LOS, length of stay.
Values are presented as N (%) or median [interquartile range] (range).
Table 6.
Matched Postoperative Clinical Outcomes and Survival
| No IABP (N = 32, 50%) | IABP (N = 32, 50%) | Estimated effect (IABP vs no IABP), [95% CI], p-value | |
|---|---|---|---|
| Hospital LOS (days) | 33 [25,48] (15,96) | 39 [29,47] (15,102) | log(LOS) 087 higher for IABP group, [−0.1430.316], p = 0.452. |
| ICU LOS (days) | 10 [7,16] (4,69) | 10 [8,14] (5,98) | log(LOS) 0.016 lower for IABP group, [−0.375−0.343], p = 0.931 |
| Mechanical Ventilation (hours) | 27 [22,48] (18,201) | 32 [22,48] (15,384) | log(vent hours) 0.106 lower for IABP group, [−0.271, 0.483], p = 0.577 |
| Respiratory complication | 12 (37.5) | 5 (15.6) | OR = 0.38 [0.123,1.20], p = 0.101 |
| Right heart failure | 16 (50.0) | 15 (46.9) | OR = 1.06 [0.31,3.66], p = 0.923 |
| CVA | 1 (3.1) | 0 (0) | OR non-estimable, p = 1 |
| Infection | 6 (18.8) | 9 (28.1) | OR = 1.97 [0.617,6.29], p = 0.252 |
| Hemorrhagic event | 7 (21.9) | 5 (15.6) | OR = 0.79 [0.226,2.79], p = 0.718 |
| Dialysis | 4 (12.5) | 4 (12.5) | OR = 0.72 [0.148,3.53], p = 0.690 |
| Heart transplant | 8 (25.0) | 9 (28.1) | OR = 1.4 [0.448,4.36], p = 0.565 |
| 1-month mortality | 0 (0) | 1 (2.8) | OR non-estimable, p = 1 |
| 6-month mortality | 4 (12.5) | 5 (15.6) | OR = 1.3 [0.31,5.35], p = 1.00 |
| 12-month mortality | 8 (25.0) | 7 (21.9) | OR = 0.84 [0.26,2.68], p = 1.00 |
CI, confidence interval; CVA, cerebrovascular accident; IABP, intra-aortic balloon pump; ICU, intensive care unit; LOS, length of stay; OR, odds ratio; Vent, ventilator.
Values are presented as N (%) or median [interquartile range] (range).
Changes in hemodynamic parameters
Patients supported with preoperative IABP experienced greater hemodynamic improvements from admission to pre-LVAD implantation and from admission to post-LVAD implantation. After matching, IABP patients had greater reductions in systolic PAP (median [IQR]: −18.5 [−32.5,−13.0] vs −8.5 [−15.0,−2.0] mm Hg, p = 0.0095) and PCWP (median [IQR]: −16.5 [23.3,−11.5] vs −12 [−2,−17.5] mm Hg, p = 0.019) and a greater increase in CI (median [IQR]: 0.8 [0.6,1.3] vs 0.3 [0,0.8], p = 0.018) from admission to pre-LVAD implantation. Additionally, patients supported with preoperative IABP experienced greater hemodynamic improvements in post-LVAD versus admission PCWP before and after matching as shown in Table 7 and Table 8, respectively.
Table 7.
Unmatched Changes in Hemodynamic Parameters
| Overall (N = 189) | No IABP (N = 136, 71.2%) | IABP (N = 53, 28.04%) | p | N (%) missing | |
|---|---|---|---|---|---|
| Systolic PAP Postop-Preop | −4 [−8,6] (−45,37) |
−5 [−8.0,−0.3] (−45,37) |
6 [−4,11] (−24,20) |
0.143 | 29 (15.2) |
| RA Pressure Postop-preop | - | −1 [−3.5,2] (−13,11) | −1 [−3,8] (−10,26) |
0.004 | 148 (77.5) |
| CI postop-preop | −0.2 [−1.6,0.5] (−13.2,2.2) |
−1.1 [−1.7,0.2] (−13.2,2.2) |
0.4 [−1.3,1.1] (−2.1,3.4) |
0.001 | 111 (58.1) |
| PCWP postop-preop | −16 [−25,−9.0] (−62,17) |
−15 [−23,−6.8] (−40,17) |
−20 [−25,−12] (−62,8) |
0.004 | 72 (37.7) |
| Admission Pulmonary Artery Pulsatility Index | 2.16 [1.47, 3.02] (1.14, 4.58) | 2.15 [1.53, 3.11] (1.14, 4.58) | 2.25 [1.47, 3.02] (1.36, 3.08) | 1.0 | 0 (0) |
| Systolic PAP (closest preop to OR)-Systolic PAP0 | −4 [−8,6] (−45,37) |
−5 [−8.0,−0.3] (−45,37) |
6 [−4,11] (−24,20) |
<0.0001 | 166 (87.8) |
| RA (closest preop to OR)-RA0 | −1 [−3,5] (−13,26) | −1 [−3.5,2] (−13,11) | −1 [−3,8] (−10,26) |
0.098 | 158 (83.6) |
| CI (closest preop to OR)-CI0 | −0.4 [−1.5,0.8] (−13.5,2.9) |
−0.8 [−1.9,0.6] (−13.5,1.9) |
0.2 [−0.6,1.5] (−2.0,2.9) |
<0.0001 | 144 (76.2) |
| PCWP (closest preop to OR)-PCWP0 | −2 [−5,5] (−30,25) |
−3.5 [−6.8,3.3] (−25,10) |
2.5 [−5.0,7.0] (−30,25) |
<0.0001 | 156 (82.5) |
CI, confidence interval; IABP, intra-aortic balloon pump; PAP, pulmonary artery pressure; PCWP, pulmonary capillary wedge pressure; RA, right atrial.
Values are presented as median [interquartile range] (range).
Table 8.
Matched Changes in Hemodynamic Parameters
| No IABP (N = 32, 50%) | IABP (N = 32, 50%) | Estimated effect (IABP vs no IABP), [95% CI], p-value | |
|---|---|---|---|
| Systolic PAP Postop-Preop | −15 [−23,−6] (−48,5) | −20 [−30,−15] (−58,5) | Delta PAP 0.96 lower in IABP [0.91,1.00], p = 0.066 |
| RA Pressure Postop-preop | −0 [−6.5,3.5] (−17,5) | −6 [−9,−4] (−21,11) | Delta RA 0.932 lower in IABP [0.84,1.03], p = 0.181 |
| CI postop-preop | −1.6 [−2.1,−1.3] (−2.9,2.5) | −1.2 [−1.6,−0.12] (−3.0,3.1) | Delta CI 1.212 higher in IABP [0.81,1.81], p = 0.348 |
| PCWP postop-preop | −13 [−18,−3] (−28,6) | −21 [−24,−13] (−35,8) | Delta PCWP 6.0 lower in IABP [−11.3,−0.623], p = 0.029 |
| Admission Pulmonary Artery Pulsatility Index | 2.5 [2.3, 5.4] (2.1, 7.0) | 1.9 [1.8, 2.7] (1.1, 3.6) | log(PAPi) 0.356 lower for IABP group, [−0.63,−.0.08], p = 0.013. |
| Systolic PAP (closest preop to OR)-Systolic PAP0 | −8.5 [−15.0, −2.0] (−32.0, 4) | −18.5 [−32.5, −13.0] (−58, 4) | Delta PAP is 0.909 higher in IABP [0.24,1.58], p = 0.0095 |
| RA (closest preop to OR)-RA0 | 0 [−5.3, 3.3] (−17, 5) | −5.5 [−9.0, −3.0] (−21, 11) | Delta RA is 0.302 times higher in IABP [−0.31,0.91], p = 0.319 |
| CI (closest preop to OR)-CI0 | 0.3 [0, 0.8] (−0.8, 1.4) | 0.8 [ 0.6, 1.3], (0, 2.3) | Delta CI is 0.62 higher in IABP [0.12,1.12], p = 0.018 |
| PCWP (closest preop to OR)-PCWP0 | −12 [−2,−17.5] (−28, 5) | −16.5 [23.3, −11.5] (−35, 8) | Delta PCWP is 0.63 higher in IABP [0.11,1.15], p = 0.019 |
Values are presented as median [interquartile range] (range).
CI, confidence interval; IABP, intra-aortic balloon pump; PAP, pulmonary artery pressure; PCWP, pulmonary capillary wedge pressure; RA, right atrial.
Discussion
Preoperative IABP optimization before LVAD implantation has been proposed for use in some high-risk patients to minimize postoperative adverse event rates. Prior literature studying baseline characteristics, clinical outcomes, and hemodynamic changes among those supported with IABP prior to LVAD versus those not supported with IABP have shown conflicting results.7, 8, 10, 11 In our single-center retrospective review of 189 adult patients undergoing LVAD implantation between April 2011 and June 2019, patients supported with IABP preoperatively versus those not supported with temporary mechanical circulatory support were younger, more likely to require mechanical ventilation preoperatively, and represented worse INTERMACS profiles. These patients also had worse baseline hemodynamic parameters, including higher RA pressure and PCWP, and lower CI. Propensity-matched analysis of 32 matched pairs revealed no differences in any postoperative clinical outcomes measured, including hospital and ICU LOS, mechanical ventilation duration, right heart failure, hemorrhagic events, and survival through 1 year. IABP-supported patients experienced greater pre-LVAD and post-LVAD hemodynamic improvements.
Among 13,511 adult patients who underwent continuous-flow durable VAD implantation, preoperative temporary mechanical circulatory support (MCS) with either ECMO or IABP was associated with increased risk of major bleeding and postoperative CVA within 3 months after durable VAD implantation compared to patients not supported with temporary MCS preoperatively.12, 13 Matched and unmatched analyses of clinical outcomes specifically among LVAD patients supported with IABP preoperatively versus those not supported with temporary MCS are sparse with some studies showing differences in baseline characteristics7, 8, 10, 11; yet, they consistently find that IABP-supported patients may achieve similar or improved clinical outcomes despite similar or worse preoperative state.
Both institutional and database studies have evaluated the impact of preoperative IABP support before LVAD on postoperative outcomes and hemodynamic changes.7, 8, 10, 11 Studies showing baseline differences between IABP-supported and medically supported patients prior to LVAD consistently find that IABP-supported patients can achieve similar clinical outcomes despite worse baseline status.7, 11 DeVore and colleagues7 conducted an analysis of the INTERMACS database from 2006 to 2014, including 2,446 LVAD patients (433 patients received preoperative IABP within 48 hours prior to LVAD), and found that patients supported with IABP preoperatively had markers of more advanced disease at baseline, including worse renal and liver function, worse right ventricular function, and increased use of mechanical ventilation. While preoperative IABP use was associated with an increased rate of post-LVAD major bleeding within 7 days (17.3% vs 12.1%, p = 0.003) and longer postoperative ICU LOS (7 vs 6 days, p = 0.005), these patients experienced similar rates of postoperative short-term right heart failure and mortality despite baseline markers of higher risk in the IABP group. In the propensity-matched analysis, there was still no difference in the rate of the composite outcome of postoperative right heart failure, hepatic dysfunction, renal dysfunction, or death at 6 months.
In an institutional study, Ternus and colleagues11 conducted an unmatched analysis of 199 noninotrope-dependent, ambulatory heart failure patients who underwent durable LVAD between 2007 and 2017. At baseline, IABP-supported patients had worse functional capacity (lower peak VO2/kg), higher baseline RA pressure, PAP, and PCWP, and lower CI than medically-supported patients prior to LVAD implantation but did not differ in age, sex, BMI, medical history, NYHA classification, and indication of support (BTT or bridge to decision). Despite these differences, the authors found no difference in the primary composite end-point of stage 2 or 3 acute kidney injury, right ventricular failure, or 30-day mortality, or in each individual end-point between IABP-supported and medically-supported patients. Additionally, the IABP-supported patients had greater hemodynamic improvements, including greater relative reduction in mean PAP (−16% vs −2%, p < 0.001).
These studies suggest that patients requiring IABP preoperatively should not be expected to have a worse postoperative clinical course following LVAD placement solely based on their hemodynamic requirement for an IABP. Similar to these studies, the unmatched analysis in our study revealed that patients requiring IABP preoperatively are sicker at baseline—these patients had a higher rate of preoperative mechanical ventilation, worse INTERMACS profiles, and worse baseline hemodynamic parameters including higher RA pressure and PCWP and lower CI. While unmatched IABP-supported patients had longer hospital and ICU LOS, prolonged postoperative mechanical ventilation, and a higher rate of right heart failure, major clinical outcomes, including postoperative CVA or mortality, did not differ between groups through 1 year.
Studies evaluating IABP-supported and medically supported patients prior to LVAD implantation with similar baseline characteristics have also found similar or improved clinical outcomes among IABP-supported patients. Koudoumas and colleagues10 performed an institutional study of 10 IABP-supported LVAD patients and 16 medically-supported LVAD patients with no differences in demographic characteristics or baseline echocardiographic parameters, hemodynamic parameters (including PCWP and cardiac output), and labs representative of end-organ function. The authors found no difference in postoperative outcomes including transfusion requirements and ICU LOS, and no patients died in either group through 1-year follow-up.
In another study with matched baseline characteristics, Imamura and colleagues8 conducted a propensity-matched study of 22 pairs of INTERMACS profile 2 patients and found that IABP patients had improved postoperative course. The IABP group had shorter postoperative ICU LOS and lower perioperative ICU stay medical expenses, with no difference in 1-year survival. Similar to the results of the study by Ternus and colleagues,11 IABP patients had more improved hemodynamics, including greater reduction in central venous pressure and greater increase in CI, as well as greater reductions in serum total bilirubin and serum creatinine compared to the non-IABP group, despite no baseline hemodynamic or laboratory differences.
These matched analyses support the unmatched studies’ finding that requiring an IABP prior to LVAD implantation does not portend a worse postoperative clinical course and that these patients can in fact achieve similar clinical outcomes despite their requirement for advanced support. Our propensity-matched analysis of 32 matched pairs supports these findings with no differences in all postoperative clinical outcomes measured, including hospital and ICU LOS, mechanical ventilation duration, right heart failure, hemorrhagic events, and survival through 1 year. Notably, the rate of right heart failure did not differ between groups in propensity-matched analyses despite IABP patients having lower admission PAPi, suggestive of increased right ventricular dysfunction. By providing both unmatched and matched institutional analyses within one cohort of patients, our study complements the published literature by identifying the characteristics of patients supported with IABP prior to LVAD and providing a balanced analysis of clinical outcomes achieved among these high-risk patients.
In addition to clinical outcomes analysis, the hemodynamic benefits demonstrated by both Ternus and colleagues11 and Imamura and colleagues8 are also important to consider due to the potential impact of sustained hemodynamic dysfunction on end-organ function.14 A multitude of studies have shown an association between hemodynamic dysfunction and development of right ventricular failure post-LVAD implantation.15, 16, 17 In our study, both unmatched and matched comparisons revealed hemodynamic improvements that were greater in IABP-supported patients both from admission to pre-LVAD implantation and from admission to post-LVAD implantation. Thus, the beneficial hemodynamic effects offered by IABPs may explain the similar clinical outcomes achieved post-LVAD implantation, including right ventricular failure, despite baseline worse hemodynamic parameters.
Limitations of this study that were partially addressed by matching include the retrospective nonrandomized nature of the study, selection bias of higher risk patients in the IABP group, and a difference in baseline markers between groups. As a retrospective, nonrandomized study, we did not accurately account for whether IABP was instituted in unstable patients needing stabilization or as an optimization strategy in stable patients – while we retrospectively made this determination, it is possible that our categorization does not capture the real-time clinical decisions that were made. This may have led to selection bias of sicker patients in the IABP group with an associated difference in baseline markers between groups. Also, patients treated with IABP but failing to improve hemodynamically would be unlikely to proceed to LVAD implantation, and our study would not capture these patients. Our study attempted to address selection bias and the difference in baseline markers by providing propensity-matched analysis. However, it is possible that other variables influencing outcomes may have been missed in our retrospective review of medical records. Additionally, our manuscript covered an 8-year period during which 3 different continuous-flow LVADs were available to patients: the HeartMate II, HeartMate III, and HeartWare. It is important to acknowledge the significant variability among these devices and their potential impact on patient outcomes. This variability was not controlled for in our matched cohort due to notable reductions in matched model concordance when including this variable. Nevertheless, we hope this manuscript provides a foundation for understanding the role of IABP use in successful LVAD implantation.
Conclusions
In conclusion, IABP use during the preoperative admission before LVAD surgery is associated with hemodynamic benefits in high-risk patients. Major postoperative clinical outcomes including postoperative CVA and early and late mortality were similar between those who received preoperative IABP and those who did not although patients who received IABP had baseline markers of higher risk. In propensity-matched analyses, there were no differences in any clinical outcomes measured, including right heart failure, hemorrhagic complications, or survival through 1 year. These findings suggest that patients requiring IABP support for stabilization pre-LVAD implant have similar outcomes to those not requiring IABP support pre-LVAD implant. Although further study is needed to better characterize high-risk groups, a patient-centered individualistic approach with risk-scoring should be used to identify patients who might benefit from preoperative IABP use before LVAD surgery.
CRediT authorship contribution statement
Omar Sharaf: Conceptualization, Methodology, Writing – Original draft, Writing – Review & editing, Supervision. Hua Liu: Conceptualization, Methodology, Writing – Original draft. Matheus Falasa: Conceptualization, Writing – Original draft, Writing – Review & editing. Lindsey Brinkley: Data Curation, Formal analysis, Writing – Review & editing. Ahmet Bilgili: Data Curation, Formal analysis, Writing – Review & editing. Dan Neal: Data Curation, Formal analysis. Mohammad Al-Ani: Conceptualization, Methodology, Supervision. Juan Aranda: Conceptualization, Methodology, Supervision. Alex Parker: Conceptualization, Methodology, Supervision. Mustafa Ahmed: Conceptualization, Methodology, Supervision. Juan Vilaro: Conceptualization, Methodology, Supervision. Daniel Demos: Conceptualization, Methodology, Supervision. George Arnaoutakis: Conceptualization, Methodology, Supervision. Tomas Martin: Conceptualization, Methodology, Supervision. Thomas Beaver: Conceptualization, Methodology, Supervision. Eric Jeng: Conceptualization, Methodology, Writing – Review & editing, Supervision.
Conflict of interest statement
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
None.
Financial support
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Footnotes
Presented at ISHLT 2023 43rd Annual Meeting.
References
- 1.Teuteberg J.J., Cleveland J.C., Cowger J., et al. The Society of Thoracic Surgeons INTERMACS 2019 Annual Report: the changing landscape of devices and indications. Ann Thorac Surg. 2020;109:649–660. doi: 10.1016/j.athoracsur.2019.12.005. [DOI] [PubMed] [Google Scholar]
- 2.Kormos R.L., Cowger J., Pagani F.D., et al. The Society of Thoracic Surgeons INTERMACS Database Annual Report: evolving indications, outcomes, and scientific partnerships. Ann Thorac Surg. 2019;107:341–353. doi: 10.1016/j.athoracsur.2018.11.011. [DOI] [PubMed] [Google Scholar]
- 3.Grant A.D., Smedira N.G., Starling R.C., Marwick T.H. Independent and incremental role of quantitative right ventricular evaluation for the prediction of right ventricular failure after left ventricular assist device implantation. J Am Coll Cardiol. 2012;60:521–528. doi: 10.1016/j.jacc.2012.02.073. [DOI] [PubMed] [Google Scholar]
- 4.Patlolla B., Beygui R., Haddad F. Right-ventricular failure following left ventricle assist device implantation. Curr Opin Cardiol. 2013;28:223–233. doi: 10.1097/HCO.0b013e32835dd12c. [DOI] [PubMed] [Google Scholar]
- 5.Kurihara C., Critsinelis A.C., Kawabori M., et al. Frequency and consequences of right-sided heart failure after continuous-flow left ventricular assist device implantation. Am J Cardiol. 2018;121:336–342. doi: 10.1016/j.amjcard.2017.10.022. [DOI] [PubMed] [Google Scholar]
- 6.Bellavia D., Iacovoni A., Scardulla C., et al. Prediction of right ventricular failure after ventricular assist device implant: systematic review and meta-analysis of observational studies. Eur J Heart Fail. 2017;19:926–946. doi: 10.1002/ejhf.733. [DOI] [PubMed] [Google Scholar]
- 7.DeVore A.D., Hammill B.G., Patel C.B., et al. Intra-aortic balloon pump use before left ventricular assist device implantation: insights from the INTERMACS registry. ASAIO J. 2018;64:218–224. doi: 10.1097/MAT.0000000000000629. [DOI] [PubMed] [Google Scholar]
- 8.Imamura T., Kinugawa K., Nitta D., et al. Prophylactic intra-aortic balloon pump before ventricular assist device implantation reduces perioperative medical expenses and improves postoperative clinical course in INTERMACS profile 2 patients. Circ J. 2015;79:1963–1969. doi: 10.1253/circj.CJ-15-0122. [DOI] [PubMed] [Google Scholar]
- 9.Interagency Registry for Mechanically Assisted Circulatory Support. Appendix A - adverse event definitions. UAB School of Medicine. 〈https://www.uab.edu/medicine/intermacs/intermacs-documents〉, accessed July 25, 2020.
- 10.Koudoumas D., Malliaras K., Theodoropoulos S., Kaldara E., Kapelios C., Nanas J. Long-term intra-aortic balloon pump support as bridge to left ventricular assist device implantation. J Card Surg. 2016;31:467–471. doi: 10.1111/jocs.12759. [DOI] [PubMed] [Google Scholar]
- 11.Ternus B., Behfar A., Schirger J., et al. Outcomes of ambulatory heart failure patients managed with an intra-aortic balloon pump before left ventricular assist device implantation. ASAIO J. 2021;67:430–435. doi: 10.1097/MAT.0000000000001249. [DOI] [PubMed] [Google Scholar]
- 12.Ton V.K., Xie R., Hernandez-Montfort J.A., et al. Short- and long-term adverse events in patients on temporary circulatory support before durable ventricular assist device: an IMACS registry analysis. J Heart Lung Transpl. 2020;39:342–352. doi: 10.1016/j.healun.2019.12.011. [DOI] [PubMed] [Google Scholar]
- 13.Hernandez-Montfort J.A., Xie R., Ton V.K., et al. Longitudinal impact of temporary mechanical circulatory support on durable ventricular assist device outcomes: an IMACS registry propensity matched analysis. J Heart Lung Transpl. 2020;39:145–156. doi: 10.1016/j.healun.2019.11.009. [DOI] [PubMed] [Google Scholar]
- 14.Verbrugge F.H., Guazzi M., Testani J.M., Borlaug B.A. Altered hemodynamics and end-organ damage in heart failure: impact on the lung and kidney. Circulation. 2020;142:998–1012. doi: 10.1161/CIRCULATIONAHA.119.045409. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Read J.M., Azih N.I., Peters C.J., et al. Hemodynamic reserve predicts early right heart failure after LVAD implantation. J Heart Lung Transpl. 2022;41:1716–1726. doi: 10.1016/j.healun.2022.07.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Wagner T., Bernhardt A.M., Magnussen C., Reichenspurner H., Blankenberg S., Grahn H. Right heart failure before LVAD implantation predicts right heart failure after LVAD implantation - is it that easy? J Cardiothorac Surg. 2020;15:113. doi: 10.1186/s13019-020-01150-x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Boegershausen N., Zayat R., Aljalloud A., et al. Risk factors for the development of right ventricular failure after left ventricular assist device implantation - a single-centre retrospective with focus on deformation imaging. Eur J Cardiothorac Surg. 2017;52:1069–1076. doi: 10.1093/ejcts/ezx123. [DOI] [PubMed] [Google Scholar]