The presence of peripheral arterial disease (PAD) in patients with stable coronary artery disease is associated with an increased long-term risk of death, myocardial infarction, and stroke. However, the effect of PAD on short-term outcomes in patients with acute myocardial infarction is less well understood. A total of 9,015 consecutive patients with acute myocardial infarction from the New York State Coronary Angioplasty Reporting System database, all of whom had undergone primary percutaneous coronary intervention in 1998 and 1999, were analyzed. The diagnosis of PAD was determined by a history of aortoiliac, femoral-popliteal, or carotid disease. A logistic regression model was used to determine the relation between PAD and in-hospital death and major adverse cardiovascular events, which included a composite of death, recurrent myocardial infarction, stroke, acute vessel occlusion, stent thrombosis, emergency coronary artery bypass surgery, and vascular injury. PAD had been diagnosed in 529 (5.9%) of the 9,015 patients. Patients with PAD had greater rates of diabetes mellitus, hypertension, and chronic kidney disease and were significantly more likely to develop heart failure, cardiogenic shock, and hemodynamic instability. The incidence of major adverse cardiovascular events was significantly greater in patients with PAD than in patients without PAD (20.4% vs 7.0%, p <0.001). Similarly, the in-hospital mortality rate was significantly greater among the patients with PAD (13% vs 3.8%, p <0.001). After adjusting for the baseline and procedural characteristics, PAD remained an independent predictor of in-hospital mortality (odds ratio 2.2, 95% confidence interval 1.7 to 3.0, p <0.001). In conclusion, PAD was independently associated with a doubling of the in-hospital mortality risk among patients undergoing primary percutaneous coronary intervention for acute myocardial infarction.
Patients with combined coronary artery disease (CAD) and peripheral arterial disease (PAD) who undergo percutaneous coronary intervention (PCI) have experienced reduced procedural success and more in-hospital complications. A pooled analysis of 8 large, randomized PCI trials established PAD as an independent predictor of short- and long-term mortality among patients with stable CAD. Furthermore, pre-existing PAD in patients presenting with acute coronary syndromes significantly increases the risk of in-hospital events, including mortality. Currently, only one published study has evaluated the effect of PAD on outcomes in patients undergoing emergent PCI for acute myocardial infarction (AMI). The objective of the present study was, therefore, to determine the effect of PAD on in-hospital mortality in patients with AMI who were undergoing primary PCI.
Methods
The study population was drawn from 98,564 consecutive patients who had undergone PCI in New York State in 1998 and 1999. Of this group, 9,015 patients had undergone primary PCI for AMI and constituted the study population. The vascular disease burden was assessed by documentation of aortoiliac, femoral-popliteal, and carotid disease on the case report form for each patient undergoing PCI. No distinction was made for whether the vascular disease was determined from patient symptoms, noninvasive test findings, or a previous endovascular procedure or vascular surgery. For the present analysis, the patients were stratified into 3 groups: CAD alone, CAD and PAD with involvement of one vascular territory, and CAD and polyvascular (>1 vascular territory) disease.
The Coronary Angioplasty Reporting System of the New York State Department of Health contains information regarding every patient who undergoes PCI in the New York state. The data elements in the registry include patient demographic information, baseline clinical characteristics, risk factors, angiographic characteristics (including lesion location and morphologic type), in-hospital outcomes, complications, and discharge date and disposition. All hospitals and their catheterization laboratories are responsible for the accurate documentation and transfer of data. The Department of Health has conducted periodic site visits to check the accuracy of data entry, and errors and discrepancies are brought to the attention of each laboratory to be rectified. The primary outcome of interest in the present analysis was in-hospital mortality and major adverse cardiovascular events (MACE), defined as a composite of death, recurrent myocardial infarction, stroke, acute vessel occlusion, stent thrombosis, emergency coronary artery bypass surgery, and iatrogenic vascular injury requiring surgical repair at the catheterization site.
The categorical variables were compared using chi-square analysis. Continuous variable are presented as the mean ± SD and were compared using Student’s t test or the Wilcoxon rank sum test, as appropriate. Multigroup comparisons were done using analysis of variance. To determine the independent predictors of in-hospital MACE and mortality, a stepwise multiple logistic regression analysis was performed that incorporated the relevant clinical and procedural variables, in addition to those with a univariate p value of <0.10. The variables included in the model were age, gender, hypertension, history of congestive heart failure, diabetes mellitus, chronic kidney disease, and previous bypass surgery. All p values are 2-tailed, and all confidence intervals reported are at 95%. Statistical significance was defined as p <0.05. All analyses were performed using the Statistical Package for Social Sciences, version 11.0, statistical analysis program (SPSS, Chicago, Illinois).
Results
Of the 9,015 patients undergoing primary PCI for AMI, 529 (5.9%) had previously been diagnosed with PAD, including aortoiliac (n = 212), femoral-popliteal (n = 230), and carotid (n = 190) disease. The baseline characteristics of the study population are listed in Table 1 . The procedural characteristics are listed in Table 2 . The PAD group more commonly had lesions involving the proximal left anterior descending coronary artery or the left main artery. The mean ejection fraction was numerically lower in the PAD group, but the difference did not reach statistical significance.
| Variable | Isolated CAD (n = 8,486) | CAD and PAD (n = 529) | p Value |
|---|---|---|---|
| Mean age (years) | 60.2 ± 12.6 | 68.9 ± 10.7 | <0.001 |
| Women | 28.0% | 40.0% | <0.001 |
| Hypertension | 54.8% | 71.6% | <0.001 |
| Diabetes mellitus | 16.9% | 28.2% | <0.001 |
| Previous stroke | 0.6% | 1.9% | <0.001 |
| Smoking | 94.8% | 25.7% | 0.106 |
| Chronic obstructive pulmonary disease | 4.4% | 10.8% | <0.001 |
| Chronic kidney disease | 0.9% | 3.6% | <0.001 |
| Previous coronary artery bypass grafting | 6.0% | 18.9% | <0.001 |
| Previous congestive heart failure | 2.0% | 7.6% | <0.001 |
| Acute congestive heart failure | 10.2% | 22.5% | <0.001 |
| Hemodynamic instability | 5.1% | 10.8% | <0.001 |
| Cardiogenic shock | 3.7% | 7.6% | <0.001 |
| Ventricular arrhythmia | 5.2% | 6.4% | 0.205 |
| Variable | Isolated CAD (n = 8,486) | CAD and PAD (n = 529) | p Value |
|---|---|---|---|
| Unfractionated heparin | 94.7% | 94.1% | 0.580 |
| Glycoprotein IIb/IIIa inhibitors | 36.9% | 34.0% | <0.001 |
| Proximal left anterior descending disease | 44.6% | 52.7% | 0.003 |
| Left main disease | 0.7% | 3.1% | <0.001 |
| Intra-aortic balloon pump | 7.4% | 8.5% | 0.359 |
| Mean ejection fraction | 40.4 ± 19.7 | 37.3 ± 20.2 | 0.056 |
| Percutaneous coronary intervention with stent | 78.5% | 75.4% | 0.098 |
The in-hospital outcomes are listed in Table 3 . Acute vessel occlusion, catheterization site injury, and acute renal failure were significantly more common in the patients with PAD. Also, the incidence of post-PCI stroke was greater in the PAD group (1.9% vs 0.6%, p <0.001). PAD was associated with a 50% increase in the mean length of stay (9.6 vs 6.2 days, p <0.001). The in-hospital mortality rate was 13% for patients with PAD versus 3.8% for patients without PAD (p <0.001). Similarly, the incidence of MACE was significantly increased in the PAD group (20.4% vs 7.0%, p <0.001). After adjusting for the demographic, clinical characteristic, angiographic, and procedural variables, PAD remained an independent predictor of in-hospital mortality (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.7 to 3.0, p <0.001). Other independent predictors of in-hospital mortality were age (OR 1.06, 95% CI 1.05 to 1.07, p <0.001 per additional year), male gender (OR 1.4, 95% CI 1.2 to 1.8, p = 0.001), history of congestive heart failure (OR 1.8, 95% CI 1.1 to 2.8, p = 0.02), diabetes mellitus (OR 1.7, 95% CI 1.4 to 2.2, p <0.001), and chronic kidney disease (OR 5.0, 95% CI 2.8 to 8.8, p <0.001). Similarly, the presence of PAD was an independent predictor for in-hospital MACE (OR 2.3, 95% CI 1.8 to 2.9, p <0.001).
