Meta-Analysis Evaluating Calcium Channel Blockers and the Risk of Peripheral Arterial Disease in Patients With Hypertension.

Clinical studies have shown that calcium channel blockers (CCB) can mitigate the progression of atherosclerosis. Their role in the primary prevention of peripheral artery disease (PAD) is unclear. We conducted a meta-analysis of randomized control trials (RCT) to compare the impact of CCB on the incidence of PAD in patients with hypertension. A comprehensive review of the literature was performed in PubMed and Cochrane registry. Studies were included if they were RCT and had outcome data on PAD with a follow-up duration of at least 6 months. CCB formed the intervention group, whereas the control group was constituted by either placebo or active treatment with any of the other antihypertensive medications. A random-effects meta-analysis was performed, and we report odds ratio as a measure of treatment effect. Our search identified 934 trials, of which 7 RCTs with 71,971 patients fulfilled the inclusion criteria. The mean duration of follow-up was 3.8 years. In patients receiving CCB, PAD events occurred in 547 out of 27,502 patients (2%) compared with 1,263 out of 42,659 patients in the control group (3%). Based on the random-effect model, the odds for development of PAD in hypertensive patients treated with CCB compared with the control group was 0.70 (95% confidence interval of 0.58 to 0.86, p = 0.0005). In conclusion, this meta-analysis of RCTs of hypertensive patients, we found that treatment with CCB was strongly associated with a decrease in the PAD compared with other antihypertensive agents or placebo.

Quantification of myocardial blood flow with (82)Rb: Validation with (15)O-water using time-of-flight and point-spread-function modeling.

BACKGROUND: We quantified myocardial blood flow with (82)Rb PET using parameters of the generalized Renkin-Crone model estimated from (82)Rb and (15)O-water images reconstructed with time-of-flight and point spread function modeling. Previous estimates of rubidium extraction have used older-generation scanners without time-of-flight or point spread function modeling. We validated image-derived input functions with continuously collected arterial samples. METHODS: Nine healthy subjects were scanned at rest and under pharmacological stress on the Siemens Biograph mCT with (82)Rb and (15)O-water PET, undergoing arterial blood sampling with each scan. Image-derived input functions were estimated from the left ventricle cavity and corrected with tracer-specific population-based scale factors determined from arterial data. Kinetic parametric images were generated from the dynamic PET images by fitting the one-tissue compartment model to each voxel's time activity curve. Mean myocardial blood flow was determined from each subject's (15)O-water k 2 images. The parameters of the generalized Renkin-Crone model were estimated from these water-based flows and mean myocardial (82)Rb K 1 estimates. RESULTS: Image-derived input functions showed improved agreement with arterial measurements after a scale correction. The Renkin-Crone model fit (a = 0.77, b = 0.39) was similar to those previously published, though b was lower. CONCLUSIONS: We have presented parameter estimates for the generalized Renkin-Crone model of extraction for (82)Rb PET using human (82)Rb and (15)O-water PET from high-resolution images using a state-of-the-art time-of-flight-capable scanner. These results provide a state-of-the-art methodology for myocardial blood flow measurement with (82)Rb PET.

Enhanced sensitivity of dobutamine stress echocardiography by observing wall motion abnormalities during the recovery phase after acute beta-blocker administration.

Dobutamine stress echocardiography (DSE) has a modest sensitivity for detecting single-vessel coronary artery disease (CAD). This study assessed the additional diagnostic value of new or worsening wall motion abnormalities during recovery after acute administration of beta blockers. The study population consisted of 200 patients (mean 59 +/- 11 years of age, 144 men), who underwent DSE. Images were acquired at rest, low dose, peak dose, and during recovery. Patients received intravenous metoprolol (1 to 5 mg/min). The dose was adjusted to achieve a recovery heart rate within a 10% range of heart rate at rest. Coronary angiography was performed within 2 months. Inducible new wall motion abnormalities were observed in 168 patients (84%) at peak stress. An additional 14 patients (7%) developed new or worsening wall motion abnormalities during recovery. CAD was detected in 182 patients (86 had single-vessel CAD). Sensitivity, specificity, and accuracy of DSE were 88%, 65%, and 73% at peak stress and 97%, 65%, and 74% during recovery. Sensitivity was particularly higher during recovery than during peak stress in patients with single-vessel CAD (98% vs 81%, p <0.001). In conclusion, assessment of wall motion abnormalities during the recovery phase after acute beta blockade improves sensitivity of DSE, particularly in patients with single-vessel CAD.