Abstract
BACKGROUND:
While early outcomes of the Konno-Rastan and modified Konno procedures are known, long-term outcomes remain undetermined. Our objective was to examine long-term clinical and echocardiographic outcomes.
METHODS:
Retrospective review was performed of patients undergoing Konno-Rastan and modified Konno for complex left ventricular outflow tract (LVOT) obstruction from January 1980 to January 2021. The Ross-Konno procedure was excluded due to its often limited ventriculotomy.
RESULTS:
A total of 92 patients were identified: 73 Konno-Rastan and 19 modified Konno. The modified Konno group was significantly younger (6 [2,12] years versus 16 [9,32], p=0.001). LVOT obstruction was multilevel (39/92 [42.4%]), tunnel subaortic (35/92 [38.0%]), or aortic valve (AV) stenosis/annular hypoplasia (18/92 [19.6%]). Shone syndrome was present in 20/92 (21.7%) patients. Operative mortality was 7/92 (7.6%); 4/86 (4.7%) in elective versus 3/6 (50.0%) in urgent cases (p=0.005). Median follow-up was 12 (5,22) years. AV/LVOT mean gradient was 13 (10,18) mmHg at one year but gradually increased to 25 (13,46) mmHg at 10 years. Ejection fraction remained normal. Freedom from reoperation at 5 and 10 years was 77.2% and 58.4% among Konno-Rastan and 57.7% and 41.7% among modified Konno patients (p=0.28). Overall survival at 5, 10, and 15 years was 82.9%, 76.3%, and 65.5%. Risk factors for mortality included older age, New York Heart Association Class III/IV, longer cardiopulmonary bypass time, and multilevel LVOT obstruction.
CONCLUSIONS:
While LVOT obstruction is alleviated early, recurrent LVOT obstruction occurs over time after Konno-Rastan and modified Konno procedures. Additionally, despite preserved left ventricular systolic function, late overall survival is poor in this young population.
Complex left ventricular outflow tract (LVOT) obstruction involves two or more levels of the outflow tract (subvalvular, valvular, or supravalvular). Surgical management is challenging and many patients require multiple operations to relieve obstruction.1 Surgical technique evolved from apicoaortic conduits to aortoventriculoinfundibuloplasty (Konno-Rastan procedure), described separately by Konno and Rastan.2,3 As the efficacy of the Konno-Rastan in relieving complex left ventricular (LV) outflow tract obstruction (LVOTO) became more apparent, similar septal enlargement techniques were applied to patients with tunnel subaortic obstruction without aortic valve (AV) pathology resulting in the modified Konno, avoiding aortic valve replacement (AVR).
Konno-Rastan and modified Konno have been shown to successfully relieve complex LVOTO through mid-term follow-up; however, late mortality and rates of AV reoperation have been variable with limited long-term follow-up.1,4–12 Accordingly, the purpose of this study was to examine long-term clinical and echocardiographic outcomes following the Konno-Rastan and modified Konno procedures.
PATIENTS AND METHODS
A retrospective review was performed of patients undergoing Konno-Rastan and modified Konno for complex left ventricular outflow tract (LVOT) obstruction from January 1980 to January 2021 from a prospectively maintained institutional database. Figure 1 demonstrates the distribution of Konno-Rastan, modified Konno, and Ross-Konno procedures that have been performed over the study period. The modified Konno and Konno-Rastan have been performed with decreasing frequency while the Ross-Konno has increased over time. Patients undergoing Ross-Konno were excluded due to the often limited septal incision. This study was approved on April 13, 2021 by the Mayo Clinic Institutional Review Board with waiver of informed consent. In general, isolated tunnel subaortic stenosis is managed with modified Konno and Konno-Rastan is applied when concomitant AV pathology is present. Details of each procedure have been previously described.1,13
Figure 1:
Procedure Distribution over the Study Period. Distribution of Konno-Rastan, Modified Konno, and Ross-Konno procedures over the study period.
Patients were categorized by site of obstruction: multilevel LVOTO, tunnel subaortic stenosis, or isolated AV stenosis/regurgitation with annular hypoplasia. Echocardiography reports where LV systolic function was only described were empirically assigned LV ejection fraction of 60% for “normal” and 70% for “hyperdynamic”.14 Aortic annulus Z-score was calculated using reference data from the Pediatric Heart Network Normal Echocardiogram Database.15 Echocardiography and New York Heart Association (NYHA) functional class were censored at reoperation or death. Early AV reoperation was defined as repair or replacement within 25 months postoperatively.
Statistical analysis was performed using RStudio Version 4.0.3 (RStudio, PBC; Boston, Massachusetts) with statistical significance defined as p<0.05. Categorical variables are reported as number (%). Continuous variables are reported as median (interquartile range). Kaplan-Meier overall survival and freedom from reoperation analyses with log-rank tests were performed. Fine Gray competing analysis was used in freedom from reoperation analyses to account for mortality. Kruskal-Wallis rank sum tests and Fisher’s exact tests were performed to assess for differences between groups. Univariate and multivariable Cox proportional hazards models were used to assess risk factors for mortality and reoperation. Factors included in multivariable analysis were decided based on significant associations in univariate analysis and clinical expertise.
RESULTS
PREOPERATIVE CHARACTERISTICS
We identified 92 consecutive patients with complex LVOTO who underwent Konno-Rastan (73/92 [79.3%]) or modified Konno (19/92 [20.7%]). The modified Konno group was substantially younger than the Konno-Rastan group (6 [2,12] years versus 16 [9,32], p=0.001), and 63.0% were symptomatic (Table 1). Atrioventricular septal defect was more common in the modified Konno group (10/19 [53%] vs 7/73 [10%], p<0.001). Sites of LVOTO were multilevel (39/92 [42.4%]), tunnel subaortic (35/92 [38.0%]), or AV stenosis/hypoplasia (18/92 [19.6%]). Eighty-one (88.0%) patients had prior cardiac operations (Supplemental Table 1). Median preoperative AV/LVOT mean gradient was 59 (40,70) mmHg (Supplemental Table 2). Most cases were performed electively (86/92 [93.5%]), and concomitant procedures were common (42/92 [45.7%], Table 2).
Table 1:
Preoperative Characteristics
| Total Cohort N=92 | Konno-Rastan N=73 | Modified Konno N=19 | P-Value | ||
|---|---|---|---|---|---|
| Male | 44 (48%) | 33 (45%) | 11 (58%) | 0.32 | |
| Median Age (years) | 15 (6,29) | 16 (9,32) | 6 (2,12) | 0.001 | |
| Pediatric | 55 (60%) | 38 (52%) | 17 (89%) | 0.003 | |
| Median Weight (kg) | 41 (20,70) | 51 (26,71) | 20 (11,36) | 0.008 | |
| Median Body Surface Area (m2) | 1.3 (0.8,1.8) | 1.5 (1.0,1.8) | 0.8 (0.5,1.2) | 0.007 | |
| Symptomatic | 58 (63%) | 46 (63%) | 12 (63%) | >0.99 | |
| Dyspnea with Exertion | 54 (59%) | 42 (58%) | 12 (63%) | 0.66 | |
| Angina | 19 (21%) | 15 (21%) | 4 (21%) | 0.96 | |
| Dyspnea at Rest | 9 (10%) | 7 (10%) | 2 (11%) | 0.90 | |
| Syncope | 6 (7%) | 6 (8%) | 0 (0%) | 0.20 | |
| NYHA Classa | 0.32 | ||||
| I | 9 (24%) | 9 (26%) | 0 (0%) | ||
| II | 11 (30%) | 11 (31%) | 0 (0%) | ||
| III | 11 (30%) | 9 (26%) | 2 (100%) | ||
| IV | 6 (16%) | 6 (17%) | 0 (0%) | ||
| History of Atrial Fibrillation/Flutter | 7 (8%) | 6 (8%) | 1 (5%) | 0.67 | |
| Prior Stroke | 6 (7%) | 6 (8%) | 0 (0%) | 0.20 | |
| Shone Syndrome | 20 (22%) | 15 (21%) | 5 (26%) | 0.55 | |
| DiGeorge Syndrome | 1 (1%) | 1 (1%) | 0 (0%) | 0.61 | |
| Other Congenital Heart Defects | |||||
| Bicuspid Aortic Valve | 36 (39%) | 31 (42%) | 5 (26%) | 0.20 | |
| Ventricular Septal Defect | 23 (25%) | 15 (21%) | 8 (42%) | 0.05 | |
| Atrial Septal Defect | 21 (23%) | 10 (14%) | 11 (58%) | <0.001 | |
| Coarctation | 20 (22%) | 16 (22%) | 4 (21%) | 0.94 | |
| Atrioventricular Septal Defect | 17 (18%) | 7 (10%) | 10 (53%) | <0.001 | |
| MV Pathologyb | 32 (35%) | 19 (26%) | 13 (68%) | <0.001 | |
| Site of LVOTO | <0.001 | ||||
| Multilevel | 39 (42%) | 34 (47%) | 5 (26%) | ||
| Tunnel Subaortic Stenosis | 35 (38%) | 21 (29%) | 14 (74%) | ||
| Valvular Stenosis + Annular Hypoplasia | 18 (20%) | 18 (25%) | 0 (0%) | ||
| Preoperative ECG Rhythm | |||||
| Sinus Rhythm | 80 (87%) | 62 (85%) | 18 (95%) | 0.45 | |
| Paced | 8 (9%) | 7 (10%) | 1 (5%) | >0.99 | |
| Atrial Fibrillation | 2 (2%) | 2 (3%) | 0 (0%) | >0.99 | |
| Low Right Atrial | 2 (2%) | 2 (3%) | 0 (0%) | >0.99 | |
Adults only;
MV abnormalities, atrioventricular septal defect, >mild stenosis/regurgitation; CHD=congenital heart disease, MV=mitral valve
Bold values represent statistically significant results.
Table 2:
Operative Details
| Total Cohort N=92 | Konno-Rastan N=73 | Modified Konno N=19 | P-Value | ||
|---|---|---|---|---|---|
| Status | >0.99 | ||||
| Elective | 86 (93%) | 68 (93%) | 18 (95%) | ||
| Urgent | 6 (7%) | 5 (7%) | 1 (5%) | ||
| Patients with Prior Sternotomy | 77 (84%) | 60 (82%) | 17 (89%) | 0.73 | |
| Median # Prior Sternotomies | 1 (1,2) | 2 (1,2) | 1 (1,2) | 0.44 | |
| Aortic Valve Replacement | <0.001 | ||||
| Mechanical | 57 (62%) | 57 (78%) | 0 (0%) | ||
| Homograft | 13 (14%) | 13 (18%) | 0 (0%) | ||
| Bioprosthetic | 3 (3%) | 3 (4%) | 0 (0%) | ||
| Concomitant Proceduresa | 42 (46%) | 33 (45%) | 9 (47%) | >0.99 | |
| Tricuspid Valve Repair | 8 (9%) | 8 (11%) | 0 (0%) | 0.20 | |
| Mitral Valve Replacement | 7 (8%) | 7 (10%) | 0 (0%) | 0.34 | |
| Mitral Valve Repair | 6 (7%) | 4 (5%) | 2 (11%) | 0.60 | |
| Secondary VSD Closure | 4 (4%) | 1 (1%) | 3 (16%) | 0.03 | |
| Aortic Valve Repair | 4 (4%) | 0 (0%) | 4 (21%) | 0.001 | |
| Aortic Root Replacement | 4 (4%) | 4 (5%) | 0 (0%) | 0.58 | |
| Epicardial Pacemaker Implantation | 3 (3%) | 2 (3%) | 1 (5%) | 0.51 | |
| Atrial Septal Defect Closure | 2 (2%) | 1 (1%) | 1 (5%) | 0.37 | |
| Apicoaortic Conduit Takedown | 3 (3%) | 3 (4%) | 0 (0%) | >0.99 | |
| Arch Augmentation | 3 (3%) | 3 (4%) | 0 (0%) | >0.99 | |
| Ascending Aorta Replacement | 3 (3%) | 3 (4%) | 0 (0%) | >0.99 | |
| Coronary Artery Bypass Graft | 3 (3%) | 3 (4%) | 0 (0%) | >0.99 | |
| Pulmonary Valve Replacement | 1 (1%) | 1 (1%) | 0 (0%) | >0.99 | |
| Tricuspid Valve Replacement | 1 (1%) | 1 (1%) | 0 (0%) | >0.99 | |
| Otherb | 8 (9%) | 6 (8%) | 2 (11%) | 0.36 | |
| Cardiopulmonary Bypass Time (min) | 160 (116,220) | 173 (133,223) | 100 (80,146) | <0.001 | |
| Aortic Cross Clamp Time (min) | 112 (78,143) | 118 (89,145) | 63 (50,115) | 0.001 | |
Not mutually exclusive;
other includes obliteration septal aneurysm (1), suture closure left ventricular outflow tract aneurysm (1), patch ascending aorta repair (1), patch angioplasty branch pulmonary artery (2), patch closure posterior root/aortoventricular discontinuity (1), right coronary artery osteoplasty (1), pericardiectomy (1); VSD=ventricular septal defect
Bold values represent statistically significant results.
EARLY OUTCOMES
Operative mortality was 7/92 (7.6%); 4/86 (4.7%) in elective versus 3/6 (50.0%) in urgent cases (p=0.005). Cardiac arrest occurred in three Konno-Rastan patients: one adult with apicoaortic conduit endocarditis, a 1-year-old with severe multilevel LVOTO and heart block with pulmonary hypertension, and another 1-year-old with Shone syndrome, DiGeorge syndrome, and omphalocele. Postoperative acute heart failure occurred in one modified Konno and two Konno-Rastan patients: two were urgent cases (one neonate with reduced systolic function on dobutamine and one infant with cardiogenic shock on extracorporeal membrane oxygenation support) and one was an adult with NYHA class IV symptoms and two prior AVRs with a right coronary bypass graft. The last patient was undergoing urgent Konno-Rastan for active endocarditis required an Eloesser flap postoperatively for recurrent empyema.
Median intensive care and hospital lengths of stay were 3 (2,5) and 8 (6,12) days, respectively (Table 3). Delayed sternal closure was utilized in 11/92 (12.0%) patients. Pacemakers for new complete heart block were implanted in 8/92 (8.7%). Of those, preoperative ECG showed first degree atrioventricular block in two and right bundle branch block in one.
Table 3:
Early & Late Outcomes
| Total Cohort | Konno-Rastan | Modified Konno | P-Value | |
|---|---|---|---|---|
| Early Outcomes | N=92 | N=73 | N=19 | |
| Operative Mortality | 7 (8%) | 6 (8%) | 1 (5%) | >0.99 |
| Median Postoperative LOS (days) | 8 (6,12) | 9 (7,13) | 7 (6,8) | 0.04 |
| Median Intensive Care LOS (days) | 3 (2,5) | 3 (2,5) | 3 (2,4) | 0.87 |
| Cardiac Reoperation | ||||
| Delayed Sternal Closure | 11 (12%) | 10 (14%) | 1 (5%) | 0.45 |
| Unplanned Cardiac | 7 (7.6%) | 5 (6.8%) | 2 (10.5%) | 0.63 |
| Bleeding | 6 (7%) | 4 (5%) | 2 (11%) | 0.60 |
| Complications | ||||
| Permanent Pacemaker | 8 (9%) | 7 (10%) | 1 (5%) | >0.99 |
| Cardiac Arrest | 6 (7%) | 6 (8%) | 0 (0%) | 0.34 |
| Mechanical Circulatory Support | 5 (5%) | 4 (5%) | 1 (5%) | >0.99 |
| Sepsis | 4 (4%) | 4 (5%) | 0 (0%) | 0.58 |
| Dialysis at Discharge | 2 (2%) | 2 (3%) | 0 (0%) | >0.99 |
| Stroke | 1 (1%) | 0 (0%) | 1 (5%) | 0.20 |
| Late Outcomes | N=83 | N=65 | N=18 | |
| Median Follow-up (years) | 12 (5,22) | 11 (4,21) | 15 (7,28) | 0.16 |
| Residual VSD/Patch Fracture or Dehiscence | 12 (14%) | 9 (14%) | 3 (17%) | >0.99 |
| Reoperationa,b | ||||
| Aortic Valve Replacement | 31 (67%) | 21 (64%) | 10 (77%) | 0.50 |
| Mitral Valve Repair/Replacement | 11 (24%) | 8 (24%) | 3 (23%) | >0.99 |
| VSD Repair | 6 (13%) | 4 (12%) | 2 (15%) | >0.99 |
| Tricuspid Valve Repair/Replacement | 5 (11%) | 5 (15%) | 0 (0%) | 0.30 |
| Pulmonary Valve Replacement | 2 (4%) | 1 (3%) | 1 (8%) | 0.49 |
| Heart Transplant | 2 (4%) | 2 (6%) | 0 (0%) | >0.99 |
| Other | 9 (20%) | 6 (18%) | 3 (23%) | 0.70 |
| Indications for Reoperationb | ||||
| Aortic Regurgitation | 16 (34%) | 11 (33%) | 5 (39%) | 0.74 |
| Aortic Stenosis | 18 (39%) | 13 (39%) | 5 (39%) | >0.99 |
| Mitral Valve Stenosis/Regurgitation | 11 (24%) | 8 (24%) | 3 (23%) | >0.99 |
| Subaortic Obstruction | 8 (17%) | 2 (6%) | 6 (46%) | 0.004 |
| VSD | 6 (13%) | 4 (12%) | 2 (15%) | >0.99 |
| Endocarditis | 4 (9%) | 4 (12%) | 0 (0%) | 0.31 |
| Pulmonary Valve Stenosis/Regurgitation | 2 (4%) | 1 (3%) | 1 (8%) | 0.49 |
| Other | 8 (17%) | 7 (21%) | 1 (8%) | 0.41 |
N=# of patients undergoing reoperation, total cohort N=46, Konno-Rastan N=33, Modified Konno N=13;
not mutually exclusive; LOS=length of stay; VSD=ventricular septal defect
Bold values represent statistically significant results.
LATE MORTALITY
Follow-up was complete in 83/85 (97.6%) of hospital survivors and median follow-up was 12 (5,22) years. Overall survival at 5, 10, and 15 years was 82.9%, 76.3%, and 65.5%, respectively, and did not differ between Konno-Rastan and modified Konno groups (p=0.27, Figure 2). When age was considered within the Konno-Rastan group (the modified Konno group only had two adults), adults had worse overall survival compared to pediatric patients (p=0.004, Figure 2). Causes of late death were cardiovascular in seven (sudden cardiac death [3], congestive heart failure [2], diastolic dysfunction post heart transplant [1], endocarditis [1]), noncardiovascular in seven, and unknown in 17.
Figure 2:
Overall Survival. Overall survival subgrouped by Konno-Rastan vs Modified Konno (A) and adult vs pediatric within the Konno-Rastan group (B).
LATE REOPERATION
Freedom from reoperation at 5 and 10 years was 77.2% and 58.4% among Konno-Rastan, and 57.7%% and 41.7%% among modified Konno patients (p=0.28, Figure 3). AV reoperation was most common (31/45 [68.9%]) followed by mitral valve (MV) reoperation (11/45 [24.4%], Table 3). There were two late heart transplants, both after Konno-Rastan; one 7.5 years postoperatively in a pediatric patient and another three years postoperatively in an adult. Eighteen Konno-Rastan patients underwent AV re-replacement for aortic stenosis or regurgitation; valves that had been implanted during the Konno-Rastan were homograft (8/18 [44.4%]), bioprosthetic (2/18 [11.1%]), and mechanical (8/18 [44.4%]). Freedom from reoperation within the Konno-Rastan group did not differ between pediatric and adult patients (p=0.96, Figure 3). However, all eight of the mechanical AVR patients requiring AV re-replacement were <10-years-old at the time of Konno-Rastan with a median implanted valve size of 19 (19,21) mm. Pre-discharge median AV/LVOT mean gradient for those eight patients was 14 (13,18) mmHg following Konno-Rastan.
Figure 3:
Freedom from Reoperation. Freedom from reoperation subgrouped by Konno-Rastan vs Modified Konno (A) and adult vs pediatric within the Konno-Rastan group (B).
Four modified Konno patients required early reoperation (<25 months) for AVR (persistent aortic/subaortic stenosis [3], aortic regurgitation [1]). When comparing these four to the six modified Konno patients who required later AVR, there were no differences in age, prevalence of bicuspid AV, preoperative or pre-discharge mean AV/LVOT gradient, aortic regurgitation, septal thickness, or aortic annulus Z-score. There were four patients in the Konno-Rastan group who required early AV re-replacement (endocarditis [2], homograft regurgitation [1], perivalvular leak [1]).
RISK FACTOR ANALYSIS
Risk factors independently associated with death on multivariable analyses included age, cardiopulmonary bypass time, and multilevel LVOTO (Supplemental Table 3, Table 4). Preoperative NYHA class III/IV was also significant on univariate analysis, like the factors above, but could not be included due to the limited number of variables allowed in the model.
Table 4:
Multivariable Cox Proportional Hazards Model Analyses for Mortality and Reoperation
| Variablesa | Hazard Ratio (95% CI) | P-Value |
|---|---|---|
| Mortality Model | ||
| Modified Konno | 1.38 (0.55,3.46) | 0.49 |
| Age (years) | 1.02 (1.00,1.04) | 0.03 |
| Cardiopulmonary Bypass Time (min) | 1.01 (1.00,1.01) | <0.001 |
| Multilevel LVOTO | 2.11 (1.05,4.22) | 0.04 |
| Reoperation Model | ||
| Modified Konno | 1.28 (0.58,2.81) | 0.5 |
| Age (years) | 0.99 (0.96,1.01) | 0.2 |
| Aortic Annulus Z-Score | 1.09 (0.97,1.23) | 0.1 |
| Multilevel LVOTO | 1.16 (0.65,2.04) | 0.6 |
Each model limited to 4 variables due to number of events; CI=confidence interval; LVOTO=left ventricular outflow tract obstruction
Bold values represent statistically significant results.
LONG-TERM ECHOCARDIOGRAPHIC DATA
The AV/LVOT mean gradient was 13 (10,18) mmHg at one year postoperatively, but gradually increased to 25 (13,46) mmHg at 10 years (Figure 4). LVEF was preserved over 10 years postoperatively (Figure 4). At last follow-up, 62/80 (77.5%) patients were in NYHA class I-II. Longitudinal echocardiographic data are presented in Table 5.
Figure 4:
10-Year Echocardiographic Follow-Up. Mean aortic valve/left ventricular outflow tract (AV/LVOT) gradient (A) and left ventricular ejection fraction (B) over 10 years. D/C=discharge; Preop=preoperative; CPB=cardiopulmonary bypass; Q=quartile
Table 5:
Longitudinal Echocardiographic Outcomes
| Pre-Op (N=92) | Pre-D/C (N=82) | 3 Years (N=27) | 5 Years (N=28) | 7 Years (N=23) | 10 Years (N=18) | P-Value | |
|---|---|---|---|---|---|---|---|
| LVEF (%) | 69 (61,74) | 60 (56,67) | 65 (60,71) | 61 (58,69) | 66 (60,69) | 60 (56,64) | <0.001 |
| LVEDD | 43 (35,49) | 38 (32,46) | 42 (38,47) | 44 (40,50) | 45 (42,51) | 48 (46,51) | <0.001 |
| LVESD | 23 (18, 28) | 22 (18,29) | 26 (21,29) | 28 (22,30) | 29 (25,30) | 31 (29,34) | <0.001 |
| Mean AV/LVOT Gradient (mmHg) | 59 (40,70) | 14 (9,19) | 21 (12,25) | 20 (15,30) | 25 (20,37) | 25 (13,46) | <0.001 |
| Aortic Regurgitation | <0.001 | ||||||
| None | 21 (24%) | 62 (77%) | 13 (50%) | 12 (43%) | 7 (32%) | 5 (29%) | |
| Mild/Mild-Moderate | 30 (35%) | 16 (20%) | 9 (35%) | 11 (39%) | 8 (36%) | 9 (53%) | |
| ≥Moderate | 35 (41%) | 3 (4%) | 4 (15%) | 5 (18%) | 7 (32%) | 3 (18%) | |
| Aortic Stenosis | <0.001 | ||||||
| None | 3 (4%) | 67 (84%) | 14 (54%) | 15 (56%) | 10 (53%) | 12 (71%) | |
| Mild/Mild-Moderate | 4 (5%) | 11 (14%) | 7 (27%) | 5 (19%) | 3 (16%) | 1 (6%) | |
| ≥Moderate | 75 (92%) | 2 (23%) | 5 (19%) | 7 (26%) | 6 (32%) | 4 (24%) | |
| Pulmonary Regurgitation | 0.26 | ||||||
| None | 35 (71%) | 25 (61%) | 13 (93%) | 8 (50%) | 7 (47%) | 8 (73%) | |
| Mild/Mild-Moderate | 10 (20%) | 11 (27%) | 1 (7%) | 7 (44%) | 6 (40%) | 3 (27%) | |
| ≥Moderate | 4 (8%) | 5 (12%) | 0 (0%) | 1 (6%) | 2 (13%) | 0 (0%) |
AV=aortic valve; D/C=discharge; LV=left ventricular; LVEDD=left ventricular end-diastolic diameter; LVEF=LV ejection fraction; LVESD=left ventricular end-systolic diameter; LVOT=left ventricular outflow tract
Bold values represent statistically significant results.
COMMENT
Konno-Rastan and modified Konno effectively relieve complex LVOTO over early to mid-term follow-up. However, early mortality is significant in this complex patient population, especially when operation is urgent, and postoperative complications are not uncommon, consistent with previous studies.1,4–11 Importantly, the longer follow-up in this study demonstrates recurrent LVOTO over the mid-to-long term period as well as significant rates of reoperation and late mortality in this young population.
LATE MORTALITY
Previously reported mortality data from our institution and others have been limited to mid-term results.1,4,6–8,10 Among studies with adequate late follow-up, survival ranges 85–92% at 10 years and 81–88% at 15 years.5,9,11 The overall survival rates observed in this study are substantially lower, 76.3% at 10 and 65.5% at 15 years, despite similar rates of operative mortality and postoperative complications. Age appears to have a significant impact on mortality; however, the adults are relatively young at operation.
At times the Ross-Konno operation has been considered alongside Konno-Rastan and modified Konno. While the Ross-Konno has similarities, and also addresses LVOTO, important differences should be noted. First, in the setting of a durable autograft, we would expect the Ross-Konno to require less reinterventions on the AV and root. Sustained durability of the AV also places less stress on the ventricle, as opposed to a pressure and/or volume load on the LV that then needs to undergo another cross-clamp. Second, the Ross-Konno does not require such a deep ventriculotomy compared to Konno-Rastan or modified Konno, and may not necessitate prosthetic patch material as the autograft cuff can fill this defect. Therefore, there is living tissue within that portion of the septum, and this may be advantageous long-term. So, while long-term survival following the Ross-Konno operation (79–86% at 10 years) appears to be better than that observed in this cohort of Konno-Rastan and modified Konno, Ross-Konno is more often preferred with isolated AV/LVOT disease with different physiological consequences, as well as in a younger patient population.16–18 Nonetheless, based on the disappointing long-term results in this cohort, consideration should be made of alternative treatments for complex LVOTO such as other root enlargement techniques or Ross-Konno in experienced hands. Our institution has increasingly been utilizing the Ross-Konno, with only four of the 18 Konno-Rastan procedures for isolated valvular stenosis with annular hypoplasia performed after 2010.
VENTRICULAR FUNCTION
The impact of the septal and right ventricular incisions and patches on cardiac function and electromechanical dyssynchrony over time is hard to quantify, especially in patients with multiple prior cardiac operations. The need for permanent pacing also contributes in part to late outcomes and has been associated with worse survival.19–21 Although several studies, including ours, demonstrate preserved LV ejection fraction over time, progressive LV diastolic dysfunction has not been shown to normalize postoperatively in either Konno-Rastan or Ross-Konno patients.9,12 LV end-diastolic and end-systolic diameter appear to gradually increase throughout the 10-year follow-up period although they remain within normal ranges. Additionally, while scarring around the VSD and RVOT patches may be a source of arrhythmia, long-term studies have not been performed. Sudden cardiac death could be a contributing factor to late mortality, as 3/7 known cardiovascular late deaths were due to sudden cardiac death.
In a cross-sectional study of Ross, Ross-Konno, and control patients, Ross-Konno patients had reduced LV global longitudinal strain, increased right ventricular-LV interventricular dyssynchrony, and increased septal LV intraventricular dyssynchrony, and this was more pronounced compared to Ross operation alone.22 While this study and prior work have not demonstrated a decrease in ejection fraction associated with aortoventriculoplasty, diastolic dysfunction and reduced global longitudinal strain typically precede decreases in systolic function, and electrical dyssynchrony adversely affects ventricular performance.22 It is unknown whether these factors will contribute to long-term systolic dysfunction, although paradoxical ventricular septal patch motion may further contribute to these issues.
MITRAL VALVE DISEASE
This cohort had a relatively high incidence of MV pathology, 34.8%, and 14.1% of patients had concomitant procedures on the MV.9–12,21 Over late follow-up, the second most common type of reoperation was on the MV (11/46 [23.9%]). Mitral regurgitation can worsen LV diastolic dysfunction, also impacting late survival. Haider et al acknowledge worse early and late outcomes in patients with multiple left-sided heart lesions, which may be attributed to MV disease.11
LATE REOPERATION
Reintervention-free survival at 5 years has been reported as 90–97% in Konno-Rastan and 68% in modified Konno patients.5,9,11 In this cohort, freedom from reoperation was 77.2% at 5 years in the Konno-Rastan and 57.7% at 5 years in the modified Konno groups. Of the 46 reoperations during the follow-up period, 31 were AV replacements/re-replacements. This parallels the long-term echocardiographic data demonstrating recurrent LVOTO in the long term with median AV/LVOT mean gradients increasing to 25 mmHg by 10 years postoperatively. There were also two patients from the Konno-Rastan group that required heart transplant during follow-up, highlighting the significant effect of prolonged LVOTO on the ventricle. While Konno-Rastan and modified Konno effectively relieve LVOTO in complex patients at mid-term follow-up, these procedures do not provide definitive relief and demonstrate disappointing late survival given the relatively young cohort.
RISK FACTOR ANALYSIS
Not surprisingly, urgent procedures had higher operative mortality compared to elective procedures, 4/86 (4.7%) in elective versus 3/6 (50.0%) in urgent cases (p=0.005). Longer cardiopulmonary bypass times and preoperative heart failure were also significant independent risk factors for mortality.1,11 However, our analysis also identified older age and multilevel LVOTO as independent risk factors for mortality. Patients with multilevel LVOTO, even after controlling for procedure type, had a significantly increased risk of death compared to isolated subaortic stenosis or valvular stenosis/annular hypoplasia. Previously identified risk factors for reoperation (annular hypoplasia, age, and modified Konno) were included in multivariable analysis but were not statistically significant.1,11
LIMITATIONS
This is a single-center, retrospective study at a large referral hospital that extends to an early era of cardiac surgery. As such, patient selection and management were nonuniform. This referral practice may limit the generalizability of our findings and selection bias is inherent in the study design. Additionally, cause of death was unknown in 17 of the late deaths which makes it difficult to distinguish cardiovascular and procedure-related mortality from other causes. Finally, the number of deaths and reoperations limited statistical power and restricted the multivariable analyses for those outcomes to four factors.
CONCLUSIONS
Operative mortality is significantly higher in urgent Konno-Rastan and modified Konno procedures than those electively performed. Additionally, while early results of Konno-Rastan and modified Konno show effective initial relief of obstruction, longer follow-up demonstrates recurrent LVOTO. Despite preserved left ventricular systolic function, late overall survival and freedom from reoperation are poor in this young patient population. Risk factors for mortality include older age, preoperative heart failure, longer cardiopulmonary bypass times, and multilevel LVOTO. While modified Konno and Konno-Rastan procedures are unavoidable in some patients with very severe multilevel LVOTO, these poor long-term results should further encourage surgeons to consider alternative strategies when feasible.
Supplementary Material
FUNDING:
This work was supported by the National Heart, Lung, and Blood Institute [R38HL150086].
Abbreviations
- AV
Aortic valve
- AVR
Aortic valve replacement
- LV
Left ventricular
- LVEF
Left ventricular ejection fraction
- LVOT
Left ventricular outflow tract
- LVOTO
Left ventricular outflow tract obstruction
- MV
Mitral valve
- NYHA
New York Heart Association
Footnotes
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Meeting Presentation: Society of Thoracic Surgeons Annual Meeting Oral Presentation, 1/21/2023, San Diego, CA.
Declaration of interests
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.
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