Barsness, Gregory W.

Peripheral arterial disease (PAD) is common in patients with severe coronary artery disease (CAD) and is considered a relative contraindication to external enhanced counterpulsation (EECP), but there are no data that define the efficacy and safety of EECP in patients with PAD. The International EECP Patient Registry (IEPR) was used to compare initial post-therapy and 2-year follow-up clinical outcomes and adverse event rates in patients with and without PAD. From January 2002 to October 2004, 2126 patients were enrolled in the IEPR, of whom 493 (23%) had a history of PAD. Immediately following EECP, the reduction in angina (≥ 1 Canadian Cardiovascular Society class) was similar in patients with and without PAD (76.6% vs 79.0%, p = 0.27) as was improvement in the Duke Activity Score Index (DASI) score (+4.7% vs +6.1%, p < 0.001). Both angina reduction and DASI score improvement were sustained at 2 years. PAD patients discontinued EECP more frequently (12.0% vs 8.5%, p < 0.05), but lower extremity ulceration did not occur more frequently in patients with PAD (3.7% vs 2.7%, p = 0.26). Rates of death (17.1% vs 8.6%, p < 0.001) and myocardial infarction (9.5% vs 5.0%, p < 0.001) were, as expected, higher in patients with PAD compared to patients without PAD at 2 years. In conclusion, while PAD patients constitute a high-risk cohort with known higher adverse event rates, EECP led to similar short- and long-term improvements in angina and quality of life for individuals with PAD compared to those without PAD.

In vitro and animal studies suggest that oxidative stress is associated with endothelial dysfunction. We tested whether local oxidative stress and nitric oxide (NO) bioavailability in the coronary circulation is associated with coronary endothelial dysfunction in humans. Blood samples were obtained simultaneously from the left main coronary artery and the coronary sinus for measurement of F2-isoprostanes, myeloperoxidase, nitrotyrosine, and superoxide dismutase in 20 patients without significant coronary disease. Afterward, coronary blood flow and the vascular response to intracoronary acetylcholine and N G -monomethyl- L -arginine (L-NMMA) were assessed. The gradient of isoprostanes between the arterial levels and coronary sinus correlated with the change in coronary artery diameter in response to acetylcholine ( r =−0.79, P <0.0001). Isoprostanes net production across the left anterior descending artery territory correlated with a decrease in superoxide dismutase activity ( r =0.66, P =0.002) and decrease in coronary artery diameter in response to L-NMMA (r s =0.48, P <0.05). Myeloperoxidase and nitrotyrosine gradients were similar in patients with endothelial dysfunction and controls. The effect of L-NMMA was similar in both groups. We conclude that coronary endothelial dysfunction in humans is characterized by local enhancement of oxidative stress without a decrease in basal NO release. This study supports the hypothesis that local oxidative stress has a role in reduction of NO bioavailability in humans with coronary endothelial dysfunction.

Background — In patients undergoing percutaneous coronary intervention (PCI) in the modern era, the incidence and prognostic implications of acute renal failure (ARF) are unknown. Methods and Results — With a retrospective analysis of the Mayo Clinic PCI registry, we determined the incidence of, risk factors for, and prognostic implications of ARF (defined as an increase in serum creatinine [Cr] >0.5 mg/dL from baseline) after PCI. Of 7586 patients, 254 (3.3%) experienced ARF. Among patients with baseline Cr <2.0, the risk of ARF was higher among diabetic than nondiabetic patients, whereas among those with a baseline Cr >2.0, all had a significant risk of ARF. In multivariate analysis, ARF was associated with baseline serum Cr, acute myocardial infarction, shock, and volume of contrast medium administered. Twenty-two percent of patients with ARF died during the index hospitalization compared with only 1.4% of patients without ARF ( P <0.0001). After adjustment, ARF remained strongly associated with death. Among hospital survivors with ARF, 1- and 5-year estimated mortality rates were 12.1% and 44.6%, respectively, much greater than the 3.7% and 14.5% mortality rates in patients without ARF ( P <0.0001). Conclusions — The overall incidence of ARF after PCI is low. Diabetic patients with baseline Cr values <2.0 mg/dL are at higher risk than nondiabetic patients, whereas all patients with a serum Cr >2.0 are at high risk for ARF. ARF was highly correlated with death during the index hospitalization and after dismissal.