Abstract
Background:
The impact of thrombocytopenia on revascularization and outcomes in patients presenting with acute myocardial infarction remains poorly understood. We sought to evaluate associations between thrombocytopenia, in-hospital management, bleeding, and cardiovascular outcomes in patients hospitalized for acute myocardial infarction in the United States.
Methods:
Patients hospitalized from 2004 to 2014 with a primary diagnosis of acute myocardial infarction were identified from the National Inpatient Sample. Management of acute myocardial infarction was compared between patients with and without thrombocytopenia. Multivariable logistic regression models were used to estimate odds of in-hospital adverse events stratified by thrombocytopenia and adjusted for demographics, cardiovascular risk factors, comorbidities, and treatment.
Results:
A total of 6,717,769 patients were hospitalized with a primary diagnosis of acute myocardial infarction and thrombocytopenia was reported in 219,351 (3.3%). Patients with thrombocytopenia were older, more likely to have other medical comorbidities, were more likely to undergo coronary artery bypass grafting (28.8% vs. 8.2%, p<0.001), and were less likely to receive a drug eluting stent (15.5% vs. 29.5%, p<0.001). After multivariable adjustment, thrombocytopenia was independently associated with nearly two-fold increased odds of in-hospital mortality (aOR 1.91, 95% CI 1.86−1.97). Thrombocytopenia was also independently associated with ischemic stroke, cardiogenic shock, cardiac arrest and bleeding complications.
Conclusions:
Patients with thrombocytopenia in the setting of acute myocardial infarction had increased odds of bleeding, cardiovascular outcomes, and mortality compared with patients without thrombocytopenia. Future investigations to mitigate the poor prognosis of patients with acute myocardial infarction and thrombocytopenia are warranted.
Keywords: Acute myocardial infarction, thrombocytopenia, mortality
INTRODUCTION
Thrombocytopenia is a common laboratory abnormality in patients presenting with acute myocardial infarction. Data on the impact of thrombocytopenia on acute myocardial infarction management and outcomes are scarce, as patients with thrombocytopenia are frequently excluded from large clinical trials.1 Some studies have addressed the associations between low platelet counts and post-myocardial infarction outcomes but have yielded conflicting results.2–6 Evidence to guide management of this high-risk population is necessary. To improve risk stratification for this vulnerable subgroup of acute myocardial infarction patients, we sought to evaluate associations between thrombocytopenia and in-hospital management, clinical outcomes and mortality among patients hospitalized for acute myocardial infarction in the United States.
Study Population
Patients hospitalized with a principal diagnosis of acute myocardial infarction between 2004 and 2014 were identified from the United States Healthcare Cost and Utilization Project’s (HCUP) National Inpatient Sample (NIS). The NIS is a nationwide repository of de-identified administrative data representing 20% of all hospital admissions in the United States.7 Patients were included if they had an International Classification of Diseases, Ninth Revision (ICD-9) code for acute myocardial infarction as a primary diagnosis. Acute myocardial infarction was defined as any initial episode of non-ST-segment elevation myocardial infarction or ST-segment elevation myocardial infarction (Supplementary Appendix). Thrombocytopenia is typically defined as a platelet count less than 150 × 103 per μL. Since discrete laboratory data are not included in the NIS administrative database, thrombocytopenia was defined by the presence of ICD-9 codes for one (or more) of the following diagnoses: primary thrombocytopenia, secondary thrombocytopenia, immune thrombocytopenic purpura, Evans’ syndrome, and congenital and hereditary thrombocytopenic purpura (Supplementary Appendix).
Outcomes and Definitions
The primary outcome was in-hospital all-cause mortality. Secondary outcomes included adverse cardiovascular events, bleeding events, and transfusions. Adverse cardiovascular events included cardiac arrest (defined by ICD-9 diagnosis code 427.5), cardiogenic shock (defined by ICD-9 diagnosis code 785.51), and acute ischemic stroke (defined by ICD-9 diagnosis codes 433.x1, 434.x1, 436, and 437.1).8,9 Bleeding events were identified by ICD-9 diagnosis and procedure codes, as previously defined (Supplementary Appendix).10,11 Management of acute myocardial infarction was identified by ICD-9 and Clinical Classification Software (CCS) procedure codes (Supplementary Appendix) and grouped into 4 mutually exclusive categories: medical therapy without invasive coronary revascularization, percutaneous coronary intervention with bare metal stents, percutaneous coronary intervention with drug eluting stents, and coronary artery bypass grafting. Patients who underwent both percutaneous coronary intervention and coronary artery bypass grafting during the index admission were classified as having undergone surgical revascularization.
Statistical Analysis
Patients with acute myocardial infarction were stratified by the presence or absence of thrombocytopenia. Categorical and continuous variables were compared using chi-square tests and t tests, respectively. Analyses of proportions over time were performed using the Mantel- Haenszel test for trend. Hierarchical multivariable logistic regression models were established to estimate odds of cardiovascular and bleeding events after adjustment for patient age, sex, race, and year of hospital discharge. Subsequent logistic regression models were adjusted for all variables in the base model and also alcohol abuse, liver disease, chronic kidney disease, any malignancy, autoimmune disorders, prior stroke, prior myocardial infarction, prior percutaneous coronary intervention, prior coronary artery bypass grafting, and treatment of current acute myocardial infarction. In all analyses, sampling weights were applied to determine national incidence estimates, incorporating pre-specified clustering and strata. All statistical analyses were performed using SPSS version 25 (IBM Corporation, Armonk NY, USA). The NIS is a publicly available, de-identified dataset, and the study was exempt from institutional board review.
Sensitivity Analysis
To explore the potential confounding due to treatment-related or hospital-acquired thrombocytopenia, we performed a sensitivity analysis excluding patients with non-primary etiologies of thrombocytopenia, such as secondary thrombocytopenia or thrombocytopenia of unspecified etiology (ICD-9 diagnosis codes 287.49 and 287.5, respectively). Patients with heparin-induced thrombocytopenia (defined by ICD-9 diagnosis code 289.84) and those with thrombocytopenia potentially related to the administration of glycoprotein IIb/IIIa inhibitors (defined by ICD-9 procedure code 99.20) were also excluded in this sensitivity analysis.
RESULTS
Baseline Characteristics
A total of 6,717,769 hospitalizations with a primary diagnosis of acute myocardial infarction were identified, among which thrombocytopenia was reported in 219,351 (3.3%). The prevalence of thrombocytopenia among acute myocardial infarction patients increased over time, from 1.9% in 2004 to 4.9% in 2014 (p trend <0.001, Figure). Patients with acute myocardial infarction and thrombocytopenia were older (median age of 72 years vs. 67 years, p<0.001) and more likely to be male (66.3% vs. 60.2%, p<0.001) than patients without thrombocytopenia. A greater proportion of patients with acute myocardial infarction and thrombocytopenia had cardiovascular and medical comorbidities, including congestive heart failure, liver disease, and malignancy, compared to those without thrombocytopenia (Table 1). Similar distributions of comorbidities and demographics were observed when the analysis was restricted to patients with primary thrombocytopenia (Supplementary Table 1). Patients with acute myocardial infarction and thrombocytopenia were less likely to present with ST-segment elevation myocardial infarction as the index diagnosis compared to those without thrombocytopenia (28.7% vs. 35.1%, p<0.001). Thrombocytopenia was also less common in patients who presented with ST-segment elevation myocardial infarction compared with non-ST-segment elevation myocardial infarction (2.7% vs. 3.6%, p<0.001).
Figure.
Table 1:
Baseline Characteristics Stratified by Presence of Thrombocytopenia
| Variable | AMI with Thrombocytopenia (n=219,351) | AMI without Thrombocytopenia (n=6,498,418) | p value |
|---|---|---|---|
| STEMI | 62,888 (28.7%) | 2,283,599 (35.1%) | <0.001 |
| NSTEMI | 156,463 (71.3%) | 4,214,819 (64.9%) | <0.001 |
| Age (mean, SE) | 70.70 (0.08) | 67.41 (0.06) | <0.001 |
| Age (median, IQR) | 72 (62 – 81) | 67 (57 – 79) | <0.001 |
| Female Sex | 73,845 (33.7%) | 2,588,374 (39.8%) | <0.001 |
| Race: White | 141,736 (64.6%) | 4,127,242 (63.5%) | <0.001 |
| Race: Black | 17,636 (8%) | 521,577 (8%) | <0.001 |
| Race: Hispanic | 151,50 (6.9%) | 394,938 (6.1%) | <0.001 |
| Race: Asian | 13,547 (6.2%) | 319,730 (4.9%) | <0.001 |
| Race: Other/Unknown | 31,282 (14.3%) | 1,134,931 (17.5%) | <0.001 |
| Tobacco use | 66,175 (30.2%) | 2,231,500 (34.3%) | <0.001 |
| Alcohol abuse | 11,894 (5.4%) | 176,413 (2.7%) | <0.001 |
| Drug abuse | 4,146 (1.9%) | 129,410 (2%) | 0.15 |
| Diabetes Mellitus | 89,697 (40.9%) | 2,314,209 (35.6%) | <0.001 |
| Obesity | 23,263 (10.6%) | 722,069 (11.1%) | 0.005 |
| Hyperlipidemia | 110,369 (50.3%) | 3,521,394 (54.2%) | <0.001 |
| Hypertension | 152,086 (69.3%) | 4,483,181 (69%) | 0.20 |
| Chronic Kidney Disease | 57,782 (26.3%) | 937,289 (14.4%) | <0.001 |
| Atrial fibrillation/flutter | 58,638 (26.7%) | 1,048,901 (16.1%) | <0.001 |
| CHF | 95,149 (43.4%) | 1,954,674 (30.1%) | <0.001 |
| Prior MI | 23,724 (10.8%) | 662,008 (10.2%) | <0.001 |
| Prior PCI | 24,038 (11%) | 739,315 (11.4%) | 0.02 |
| Prior CABG | 17,182 (7.8%) | 484,535 (7.5%) | 0.01 |
| Liver Disease | 11,606 (5.3%) | 66,561 (1%) | <0.001 |
| Any Malignancy | 33,774 (15.4%) | 621,638 (9.6%) | <0.001 |
| Leukemia/Lymphoma | 5,853 (2.7%) | 53,518 (0.8%) | <0.001 |
| HIV | 1,187 (0.5%) | 20,018 (0.3%) | <0.001 |
| Rheumatoid arthritis/collagen vascular diseases | 5,432 (2.5%) | 138,461 (2.1%) | <0.001 |
SE, standard error; IQR, interquartile range; AMI, acute myocardial infarction; STEMI, ST-segment elevation myocardial infarction; NSTEMI, non ST-segment elevation myocardial infarction; CHF, congestive heart failure; MI, myocardial infarction; PCI, percutaneous coronary intervention; CABG, coronary artery bypass grafting; HIV, human immunodeficiency virus.
In-Hospital Management of Acute Myocardial Infarction
Management of acute myocardial infarction varied significantly based on the presence or absence of thrombocytopenia. Patients with thrombocytopenia were more likely to undergo coronary artery bypass grafting (28.8% vs. 8.2%, p<0.001) and less likely to undergo percutaneous coronary intervention with a drug eluting stent (15.2% vs. 29.5%, p<0.001) compared to patients without thrombocytopenia. Comparisons of other management strategies for acute myocardial infarction between patients with and without thrombocytopenia are shown in Table 2. Overall, patterns of acute myocardial infarction management were similar when the analysis was restricted to patients with primary thrombocytopenia (Supplementary Table 2). Trends in the approach to revascularization in acute myocardial infarction patients with and without thrombocytopenia are shown in Supplementary Figure 1 and 2, respectively.
Table 2.
Management of Acute Myocardial Infarction Stratified by Presence of Thrombocytopenia
| Intervention | AMI with Thrombocytopenia (n=219,351) | AMI without Thrombocytopenia (n=6,498,418) | p value |
|---|---|---|---|
| Thrombolysis | 1,863 (0.8%) | 92,999 (1.4%) | <0.001 |
| Diagnostic Angiography | 135,330 (61.7%) | 4,220,697 (64.9%) | <0.001 |
| Coronary Revascularization | <0.001 | ||
| No Revascularization | 103,746 (47.3%) | 3,346,597 (51.5%) | |
| Bare Metal Stent | 19,059 (8.7%) | 703,081 (10.8%) | |
| Drug Eluting Stent | 33,348 (15.2%) | 1,913,970 (29.5%) | |
| CABG | 63,197 (28.8%) | 534,771 (8.2%) |
AMI, acute myocardial infarction; CABG, coronary artery bypass grafting.
Bleeding Outcomes
Bleeding during hospital admission was more common in acute myocardial infarction patients with thrombocytopenia in comparison to those without thrombocytopenia (29.3% vs. 11.4%, p<0.001; OR 3.62, 95% CI 3.48−3.76 [Table 3]). Similarly, bleeding requiring intervention occurred in 25.6% of acute myocardial infarction patients with thrombocytopenia and in 9.4% of those without thrombocytopenia (OR 3.33, 95% CI 3.22−3.45). Hemorrhagic stroke occurred more frequently in patients with thrombocytopenia in comparison to those without thrombocytopenia (0.4% vs. 0.2%, p<0.001; OR 2.09, 95% CI 1.80−2.44 [Table 3]). Patients with acute myocardial infarction and thrombocytopenia were more likely to receive transfusions of red blood cells (OR 3.37, 95% CI 3.25−3.50) and platelets (OR 8.35, 95% CI 7.77−8.97) than acute myocardial infarction patients without thrombocytopenia. Sensitivity analysis also identified patients with primary thrombocytopenia to be at a higher risk for bleeding than those without thrombocytopenia, after adjusting for demographics, comorbidities, and management of acute myocardial infarction (Supplementary Table 3).
Table 3.
Bleeding and Cardiovascular Outcomes Stratified by Presence of Thrombocytopenia
| Outcome | AMI with Thrombocytopenia (n=219,351) | AMI without Thrombocytopenia (n=6,498,418) | OR, Crude (95% CI) | aOR, Model 1 (95% CI)a | aOR, Model 2 (95% CI)b | aOR, Model 3 (95%CI)c |
|---|---|---|---|---|---|---|
| Any Bleeding | 64,166 (29.3%) | 743,614 (11.4%) | 3.62 (3.48 – 3.76) | 5.20 (5.02 – 5.39) | 4.62 (4.46 – 4.78) | 2.75 (2.64 – 2.87) |
| Bleeding Requiring Intervention | 56,262 (25.6%) | 609,432 (9.4%) | 3.33 (3.22 – 3.45) | 6.11 (5.88 – 6.35) | 5.43 (5.23 – 5.64) | 2.91 (2.76 – 3.07) |
| RBC Transfusion | 43,379 (19.8%) | 442,760 (6.8%) | 3.37 (3.25 – 3.5) | 6.62 (6.36 – 6.88) | 5.69 (5.47 – 5.91) | 3.01 (2.84 – 3.18) |
| Platelet Transfusion | 12,785 (5.8%) | 47,824 (0.7%) | 8.35 (7.77 – 8.97) | 16.7 (15.7 – 17.8) | 16.1 (15.2 – 17.1) | 2.57 (2.39 – 2.76) |
| Cardiac arrest | 12,318 (5.6%) | 189,527 (2.9%) | 1.98 (1.9 – 2.07) | 2.41 (2.32 – 2.5) | 2.36 (2.28 – 2.45) | 2.35 (2.28 – 2.44) |
| Cardiogenic Shock | 31,027 (14.1%) | 299,126 (4.6%) | 3.41 (3.29 – 3.54) | 7.16 (6.9 – 7.42) | 6.99 (6.75 – 7.25) | 5.69 (5.47 – 5.92) |
| Ischemic Stroke | 5,147 (2.3%) | 89,067 (1.4%) | 1.73 (1.62 –1.84) | 1.95 (1.85 – 2.06) | 1.89 (1.79 –1.99) | 1.61 (1.53 –1.7) |
| Hemorrhagic Stroke | 844 (0.4%) | 11,972 (0.2%) | 2.09 (1.80–2.44) | 2.78 (2.48–3.11) | 2.68 (2.40–3.00) | 2.83 (2.55–3.14) |
| Death | 21,722 (9.9%) | 366,849 (5.6%) | 1.84 (1.77 –1.9) | 1.98 (1.92 – 2.05) | 1.85 (1.8 –1.91) | 1.91 (1.86 –1.97) |
OR, odds ratio; aOR, adjusted odds ratio; CI, confidence interval; AMI, acute myocardial infarction; RBC, red blood cell.
Model 1: Adjusted for age, sex, race, and year.
Model 2: Adjusted for age, sex, race, year, alcohol abuse, liver disease, chronic kidney disease, any malignancy, autoimmune disorders, prior stroke, prior MI, prior percutaneous coronary intervention, and prior coronary artery bypass grafting.
Model 3: Adjusted for age, sex, race, year, alcohol abuse, liver disease, chronic kidney disease, any malignancy, autoimmune disorders, prior stroke, prior myocardial infarction, prior percutaneous coronary intervention, prior coronary artery bypass grafting, and treatment for current AMI (no revascularization, bare metal stent, drug eluting stent, and coronary artery bypass grafting).
Cardiovascular Outcomes
Patients presenting with acute myocardial infarction and thrombocytopenia had a nearly two-fold increased odds of in-hospital mortality compared to acute myocardial infarction patients without thrombocytopenia (9.9% vs. 5.6%, OR 1.84, 95% CI 1.77−1.90). The presence of thrombocytopenia in acute myocardial infarction was also associated with increased odds of ischemic stroke (OR 1.73, 95% CI 1.62−1.84), cardiogenic shock (OR 3.41, 95% CI 3.29−3.54), and cardiac arrest (OR 1.98, 95% CI 1.90−2.07). These associations persisted after adjustment for demographics, comorbidities, and revascularization strategies (Table 3), as well as in subgroups of patients with presenting ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction (Supplementary Tables 5 and 6). Furthermore, the association between thrombocytopenia and adverse cardiovascular outcomes and mortality was similar when the analysis was restricted to patients with primary thrombocytopenia (Supplementary Table 4).
DISCUSSION
In a nationwide cohort of 6,717,769 hospitalizations with a primary diagnosis of acute myocardial infarction, thrombocytopenia was relatively common, occurring in more than 1 of every 30 (3.3%) patients. We identified an increasing prevalence of thrombocytopenia among patients hospitalized for acute myocardial infarction, from ~2% in year 2004 to nearly 5% in 2014 (Figure). Increases in the prevalence of thrombocytopenia in the general population have also been reported over the past decades.12 The increasing prevalence of thrombocytopenia observed here may be partially attributed to improved clinical documentation or may be reflective of changes in comorbidities, medication use, and increasing age of hospitalized patients.
In this and prior studies, thrombocytopenia was associated with cardiovascular risk factors and medical comorbidities.2,4,13–15 However, in the present analysis, thrombocytopenia was independently associated with adverse outcomes, even after multivariable adjustment for demographics, comorbidities, and acute myocardial infarction treatment strategy. This is the largest analysis evaluating the impact of thrombocytopenia on outcomes of patients who present with acute myocardial infarction in the United States and the first analysis to describe acute myocardial infarction patients with primary thrombocytopenia.
Our findings indicate that the presence of thrombocytopenia was associated with significant differences in management of acute myocardial infarction compared to patients without thrombocytopenia. We observed that patients with thrombocytopenia were nearly half as likely to receive drug eluting stents compared to those without thrombocytopenia. The minimum duration of dual antiplatelet therapy and perceptions regarding bleeding risks in this population may have affected decisions regarding stent placement.16–18 Patients with thrombocytopenia were more than three-fold more likely to undergo surgical revascularization compared to patients without thrombocytopenia, despite the higher risk for bleeding complications. This pattern appeared consistently across each individual year captured in our study as well (Supplementary Figures 1 and 2). There are a few possible explanations for this finding. Prior to 2015, American College of Cardiology/American Heart Association (ACC/AHA) guidelines did not provide a recommendation for dual antiplatelet therapy after coronary artery bypass grafting in patients with acute myocardial infarction. Thus, coronary artery bypass grafting may have been preferred to percutaneous coronary intervention in patients perceived to be at high risk of bleeding who would require dual antiplatelet therapy after stent implantation. Conversely, thrombocytopenia may have resulted as a complication of prolonged hospitalization after coronary artery bypass grafting in some patients. Given the limitations of administrative coding data, the temporal sequence of coronary revascularization and thrombocytopenia cannot be ascertained. However, a similar association between thrombocytopenia and coronary artery bypass grafting was also observed in a sensitivity analysis restricting thrombocytopenia diagnoses to those that were primary in nature. (Supplementary Table 2).
Patients with thrombocytopenia were more likely to have a bleeding event during hospitalization for acute myocardial infarction compared to those without thrombocytopenia. Patients with thrombocytopenia, and particularly those with primary thrombocytopenia, were also more likely to receive red blood cell and platelet transfusions during hospitalization for acute myocardial infarction. Adjustment for revascularization strategy attenuated the odds of bleeding and transfusion among patients with thrombocytopenia (Table 3). This suggests a possible association between approaches to revascularization in thrombocytopenic patients and increased risks of bleeding and transfusion. Increased frequency of platelet and red blood cell transfusions associated with surgical revascularization in patients with thrombocytopenia may also have unmeasured downstream effects on cardiovascular outcomes. Prior studies have demonstrated red blood cell transfusions to be an independent predictor of mortality in patients with acute coronary syndromes and in patients who underwent percutaneous coronary intervention.19–20 Prior studies have also demonstrated associations between platelet transfusion and increased thrombotic events and mortality in patients with thrombocytopenia, as well as increased need for vasoactive medications, prolonged mechanical ventilation and intensive care in patients undergoing cardiac surgery.21–22 Whether transfusions are causally related to adverse outcomes or merely serve as a marker of disease severity cannot be determined from this study. Further prospective investigation is needed to clarify the relationship between revascularization strategy and bleeding complications in patients with thrombocytopenia as well as the impact of transfusions on adverse outcomes in patients with thrombocytopenia and acute myocardial infarction.
The increased risk of acute ischemic stroke in patients with thrombocytopenia overall, and after excluding patients with heparin-induced thrombocytopenia, was an unexpected finding. However, thrombocytopenia and/or bleeding may lead providers to withhold or defer anti- platelet and anticoagulant therapies, which may paradoxically increase the risk of thrombotic events. In fact, major bleeding has been previously reported to be independently associated with stroke and death in patients with acute coronary syndromes.23–25 However, as expected, we also identified an association between thrombocytopenia and hemorrhagic stroke, supporting the validity of the current data. In addition, thrombocytopenia in acute myocardial infarction was also associated with two-fold greater odds of cardiac arrest and more than five-fold greater odds of cardiogenic shock than acute myocardial infarction patients without thrombocytopenia, with similar findings in a sensitivity analysis of patients with primary thrombocytopenia.
In the present analysis we observed that thrombocytopenia was more common in patients who presented with non-ST-segment elevation myocardial infarction compared with ST-segment elevation myocardial infarction (3.6% vs 2.7%, p<0.001). The frequencies of adverse cardiovascular events were two to three-fold higher in patients with ST-segment elevation myocardial infarction compared with non-ST-segment elevation myocardial infarction, while the bleeding complications were similar in both groups. Thrombocytopenia and primary thrombocytopenia were independently associated with mortality in patients presenting with non- ST-segment elevation myocardial infarction and ST-segment elevation myocardial infarction. These data suggest that low platelet counts, regardless of the mechanism of thrombocytopenia, may identify non-ST-segment elevation myocardial infarction and ST-segment elevation myocardial infarction patients at high risk for cardiovascular complications and in-hospital mortality.
Limitations
There are limitations to these analyses. Analyses were based on administrative coding, which may be subject to coding errors or reporting bias. Unfortunately, laboratory data and platelet counts were not recorded, and therefore the severity of thrombocytopenia could not be classified. The ICD-9 classification system does not specify the acuity or chronicity of thrombocytopenia. Data regarding coronary angiography, the burden of atherosclerotic disease, and left ventricular ejection fraction were not recorded in this administrative dataset. Similarly, the use of medical therapy, including anti-platelet agents or anticoagulation, was not available for analysis. The temporality of thrombocytopenia with respect to treatment of acute myocardial infarction could not be reliably determined. This may be a particularly relevant concern for patients undergoing coronary artery bypass grafting, in whom thrombocytopenia may have developed during hospitalization. To explore this, a sensitivity analysis was performed excluding thrombocytopenia that may have been related to in-hospital management of acute myocardial infarction, including heparin-induced thrombocytopenia, glycoprotein IIb/IIIa inhibitor use, and secondary thrombocytopenia. The results of the sensitivity analysis were consistent with those of the primary analysis and illustrate the robustness of our findings. Associations between thrombocytopenia and outcomes may be due to the severity of associated comorbidities or unidentified illnesses. However, results remained consistent in magnitude and direction, even after hierarchical multivariable adjustment for a number of clinical comorbidities and after the exclusion of patients with secondary thrombocytopenia. Finally, the data set used in this analysis does not allow for outpatient follow-up or long-term outcomes beyond the index hospitalization.
CONCLUSIONS
This is the largest analysis of management and outcomes of acute myocardial infarction in patients with and without thrombocytopenia. The prevalence of thrombocytopenia in patients presenting with acute myocardial infarction increased from 1.9% in 2004 to 4.9% in 2014. Thrombocytopenia was independently associated with in-hospital bleeding, stroke, cardiovascular complications, and death, and identified acute myocardial infarction patients at high risk for in-hospital adverse outcomes. Prospective investigation into the management of acute myocardial infarction in the setting of thrombocytopenia, particularly with regard to revascularization and transfusion strategies, is necessary to mitigate the poor prognosis of this expanding population.
Supplementary Material
Clinical Significance:
The prevalence of thrombocytopenia in patients presenting with acute myocardial infarction has increased.
Thrombocytopenia in acute myocardial infarction is an independent predictor of bleeding, stroke, cardiogenic shock, and death.
Management of acute myocardial infarction differs significantly based on the presence of thrombocytopenia, but the optimal approach to revascularization and transfusions in this population remains unknown.
Funding:
Dr. Smilowitz is supported by an NYU CTSA grant, UL1 TR001445 and KL2 TR001446, from the National Center for Advancing Translational Sciences, National Institutes of Health (NIH). Dr. Newman was partially funded by the National Heart, Lung, and Blood Institute (NHLBI) of the NIH (K23HL125991). Dr. Berger was partially funded by the NHLBI of the NIH (HL114978).
Footnotes
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Conflict of Interest: None
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