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Outcomes Associated With PAD in MI With Cardiogenic Shock
Quick Takes
- Peripheral artery disease (PAD) may be considered a risk factor for poor outcomes in patients presenting with acute MI and cardiogenic shock.
- Enhanced knowledge of the risks of PAD, improved screening, and implementing guideline-recommended treatment for patients with PAD is key.
Study Questions:
What is the relationship between lower extremity peripheral artery disease (PAD) and outcomes in patients presenting with acute myocardial infarction (AMI) and cardiogenic shock?
Methods:
This retrospective study included 71,690 Medicare fee-for-service beneficiaries aged ≥65 years hospitalized at short-term acute care hospitals across the United States with a principal diagnosis of AMI and secondary diagnosis of cardiogenic shock from October 1, 2015–June 30, 2018. A total of 5.9% of patients enrolled had a prior diagnosis of PAD. The primary outcomes were all-cause in-hospital mortality and out-of-hospital mortality. Secondary in-hospital outcomes included lower extremity revascularization (endovascular, surgical, or a combination of surgical and endovascular interventions), amputation, major bleeding, cerebrovascular accident (CVA)/transient ischemic attack (TIA), and cardiac arrest. Secondary out-of-hospital outcomes included hospitalization for heart failure (HF) or AMI, and need for hospital readmission. Multivariable regression models with adjustment for potential confounders (i.e., age, gender, race, or presence of select comorbidities) were used to estimate risk. Subgroup analysis included those who underwent mechanical circulatory support (MCS) and coronary revascularization.
Results:
A total of 53% of all patients underwent coronary revascularization and 37.6% underwent treatment with MCS (18.6% intra-aortic balloon pump, 12.1% extracorporeal membrane oxygenation, and 6.9% percutaneous ventricular assist device). Patients with PAD were more likely to be non-White and had a greater burden of cardiovascular comorbidities and risk factors (tobacco use, prior AMI, chronic kidney disease, chronic obstructive pulmonary disease, congestive HF, diabetes, ischemic heart disease, and hyperlipidemia). Patients with PAD were less likely to undergo coronary revascularization (coronary artery bypass grafting [CABG]: 13.2% vs. 6.6%, percutaneous coronary intervention [PCI]: 42.7% vs. 27.3%; p < 0.001) or receive MCS (21.5% vs. 38.6%; p < 0.001) compared to patients without PAD.
Patients with PAD experienced higher rates of mortality both in-hospital (56.3% vs. 46.6%; adjusted odds ratio [OR], 1.38; 95% confidence interval [CI], 1.29-1.47; p < 0.001) and out-of-hospital (67.9% vs. 40.7%; adjusted OR, 1.78; 95% CI, 1.67-1.9; p < 0.0001) compared to patients without PAD. Patients with PAD experienced higher rates of major bleeding (2.2 vs. 1.4%; p < 0.001), amputation (1.6% vs. 0.2%; p < 0.001), lower extremity revascularization (4.1% vs. 1.9%; p < 0.001), subsequent AMI (8.9% vs. 8%; p = 0.02; though adjusted hazard ratio was not significant), HF (26.1% vs. 18.9%; p < 0.0001), and readmissions (62% vs. 56.7%; p < 0.0001) compared to patients without PAD, though rates of CVA/TIA and cardiac arrest were comparable. These findings were consistent after multivariable adjustment, except as noted for subsequent AMI. Risk of mortality in- and out-of-hospital was increased in patients with PAD who received MCS compared to those without PAD (in-hospital: adjusted OR, 1.5; 95% CI, 1.27-1.67; p < 0.001; out-of-hospital: adjusted HR, 1.64; 95% CI, 1.4-1.93; p < 0.0001). Additionally, PAD patients undergoing treatment with MCS experienced higher risk of amputation, in-hospital lower extremity revascularization, HF, and readmissions, though comparable risks of bleeding, TIA/CVA, and cardiac arrest. Patients with PAD who underwent CABG or PCI had higher risk of in-hospital mortality, and those patients undergoing PCI had a higher risk of amputation and need for lower extremity revascularization compared to patients without PAD.
Conclusions:
This study suggests that PAD is a major risk factor among patients presenting with AMI and cardiogenic shock. Comorbid PAD was associated with worse limb outcomes and decreased short- and long-term survival, even when adjusted for multiple other contributing comorbidities. In addition to lower MCS utilization and revascularization rates, those with PAD who underwent treatment with MCS had increased mortality, lower extremity revascularization, and amputation rates.
Perspective:
This large study of patients presenting with AMI and cardiogenic shock highlights the challenges associated with managing patients with a history of PAD and the importance of interdisciplinary teamwork. Patients with PAD often present with a greater number of comorbidities, particularly those associated with increased risk of coronary artery disease, and the presence of PAD offers challenges in vascular access and may portend greater short- and long-term complications. This study highlights the underdiagnosis of PAD, with only 5.9% of patients being identified as having PAD in the year prior to hospitalization. Early identification of patients with PAD and aggressive assessment of risk factors and initiation of treatment is essential, especially as a diagnosis of PAD is associated with worse outcomes in patients presenting with AMI and cardiogenic shock. While this study evaluated a number of important confounders, remaining questions regarding outcomes in a younger cohort as well as the impact of frailty, mental status, cardiac arrest at presentation, and surgical eligibility would have on outcomes remain.
Clinical Topics: Acute Coronary Syndromes, Arrhythmias and Clinical EP, Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Prevention, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), Implantable Devices, SCD/Ventricular Arrhythmias, Aortic Surgery, Cardiac Surgery and Arrhythmias, Cardiac Surgery and Heart Failure, Acute Heart Failure, Interventions and ACS, Interventions and Vascular Medicine
Keywords: Acute Coronary Syndrome, Cardiac Surgical Procedures, Coronary Artery Bypass, Heart Arrest, Heart Failure, Hemorrhage, Hospital Mortality, Ischemic Attack, Transient, Lower Extremity, Myocardial Infarction, Myocardial Revascularization, Patient Care Team, Percutaneous Coronary Intervention, Peripheral Arterial Disease, Risk Factors, Secondary Prevention, Shock, Cardiogenic, Stroke, Vascular Diseases
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