Complete Revascularization and Angina-Related Health Status in the ISCHEMIA Trial.

BACKGROUND: The impact of complete revascularization (CR) on angina-related health status (symptoms, function, quality of life) in chronic coronary disease (CCD) has not been well studied. OBJECTIVES: Among patients with CCD randomized to invasive (INV) vs conservative (CON) management in ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches), we compared the following: 1) the impact of anatomic and functional CR on health status compared with incomplete revascularization (ICR); and 2) the predicted impact of achieving CR in all INV patients compared with CON. METHODS: Multivariable regression adjusting for patient characteristics was used to compare 12-month health status after independent core laboratory-defined CR vs ICR in INV patients who underwent revascularization. Propensity-weighted modeling was then performed to estimate the treatment effect had CR or ICR been achieved in all INV patients, compared with CON. RESULTS: Anatomic and functional CR were achieved in 43.3% and 57.8% of 1,641 INV patients, respectively. Among revascularized patients, CR was associated with improved Seattle Angina Questionnaire Angina Frequency compared with ICR after adjustment for baseline differences. After modeling CR and ICR in all INV patients, patients with CR and ICR each had greater improvements in health status than CON, with better health status with CR than ICR. The projected benefits of CR were most pronounced in patients with baseline daily/weekly angina and not seen in those with no angina. CONCLUSIONS: Among patients with CCD in ISCHEMIA, health status improved more with CR compared with ICR or CON, particularly in those with frequent angina. Anatomic and functional CR provided comparable improvements in quality of life. (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches [ISCHEMIA]; NCT01471522).

Coadministration of atorvastatin prevents nitroglycerin-induced endothelial dysfunction and nitrate tolerance in healthy humans.

OBJECTIVES: We aimed to assess whether concurrent administration of atorvastatin would modify the development of tolerance and endothelial dysfunction associated with sustained nitroglycerin (GTN) therapy in humans. BACKGROUND: Animal studies have demonstrated that administration of 3-hydroxy-3 methylglutaryl coenzyme A reductase inhibitors can protect against GTN-induced endothelial dysfunction and tolerance, likely through an antioxidant mechanism. METHODS: Thirty-six healthy male volunteers were randomized to receive continuous transdermal GTN (0.6 mg/h) and placebo, atorvastatin (80 mg/day) alone, or continuous transdermal GTN (0.6 mg/h) with concurrent atorvastatin (80 mg/day), all for 7 days. On the second visit, forearm blood flow was measured with venous-occlusion strain gauge plethysmography in response to incremental infusions of acetylcholine (7.5, 15, and 30 µg/min). Acetylcholine infusions were coinfused first with saline, and repeated during the coinfusion of vitamin C (24 mg/min). Blood pressure responses to sublingual GTN (400 µg) were assessed on both visits. RESULTS: Acetylcholine responses in the GTN plus placebo group were significantly attenuated versus those in the GTN plus atorvastatin and atorvastatin groups (p < 0.01). Coinfusion of vitamin C completely restored acetylcholine responses in the GTN plus placebo group (p < 0.01 vs. saline coinfusion), but caused no change in either the atorvastatin or the GTN plus atorvastatin groups. Blood pressure responses to sublingual GTN did not significantly change between visits in subjects receiving GTN plus atorvastatin and atorvastatin alone, but were significantly blunted in the GTN plus placebo group (p < 0.05). CONCLUSIONS: The present findings demonstrate, for the first time in humans, that atorvastatin prevents both GTN-induced endothelial dysfunction and nitrate tolerance, likely by counteracting the GTN-induced increase in oxidative stress.

Observations of time-based measures of flow-mediated dilation of forearm conduit arteries: implications for the accurate assessment of endothelial function.

Endothelium-dependent flow-mediated dilation (FMD) is measured as the increase in diameter of a conduit artery in response to reactive hyperemia, assessed either at a fixed time point [usually 60-s post-cuff deflation (FMD(60))] or as the maximal dilation during a 5-min continuous, ECG-gated, measurement (FMD(max-cont)). Preliminary evidence suggests that the time between reactive hyperemia and peak dilation (time to FMD(max)) may provide an additional index of endothelial health. We measured FMD(max-cont), FMD(60), and time to FMD(max) in 30 young healthy volunteers, 22 healthy middle-aged adults, 16 smokers, 23 patients with hypertension, 40 patients with coronary artery disease, and 22 patients with heart failure. As previously reported, FMD(max-cont) was similar in healthy cohorts and was significantly blunted in smokers and all patient groups, whereas FMD(60) was significantly blunted only in heart failure patients. There was a wide within-group variability between measures of time to FMD(max) with no significant difference between normal and patient groups. Intra-arterial infusion of the nitric oxide synthase inhibitor N(omega)-monomethyl-l-arginine in eight healthy subjects resulted in a blunting of FMD(max-cont) (P < 0.001) and FMD(60) (P = 0.02) but not time to FMD(max). Both FMD(max-cont) and FMD(60) demonstrated good repeatability in 30 young healthy volunteers studied on two separate occasions (P < 0.01 for both), whereas time to FMD(max) varied widely between visits (P = not significant). In conclusion, although time to FMD(max) does not appear to be a useful adjunctive measure of endothelial health, the use of continuous diameter measurements provides important data in the study of endothelial function in healthy subjects and patients with cardiovascular disease.

Standard versus low-dose transdermal nitroglycerin: differential effects on the development of tolerance and abnormalities of endothelial function.

We compared standard (0.6 mg/h) versus low-dose (0.05 mg/h) transdermal nitroglycerin (TGTN) on acute hemodynamic parameters, the development of tolerance, and endothelial function. Study 1 randomized six healthy volunteers to receive 0.6 mg/h or 0.05 mg/h TGTN in a crossover design study (6-day washout period) with measurements of heart rate, blood pressure, radial artery waveforms, and aortic augmentation index taken at baseline and 1, 2, and 3 hours after initial TGTN application. Study 2 enrolled 24 healthy volunteers to receive 400 µg of sublingual nitroglycerin spray followed by 400 µg of inhaled salbutamol 90 minutes later. Measurements of heart rate, blood pressure, radial artery waveforms as well as aortic augmentation index were taken at baseline and at 5, 10, and 20 minutes after each treatment. They were randomized to either 0.6 mg/h or 0.05 mg/h of TGTN, and the same measurements were repeated after 6 days. In Study 1, there was no significant difference in the response to both doses (analysis of variance, P < 0.05). In Study 2, the decrease in aortic augmentation index in response to sublingual nitroglycerin and salbutamol was attenuated after sustained therapy with 0.6 mg/h of TGTN (versus 0.05 mg/h, P < 0.05). This investigation documents that 0.05 mg/h TGTN has identical acute hemodynamic effects compared with 0.6-mg/h dose without causing tolerance or endothelial dysfunction.