With aging, pulse pressure increases. A high pulse pressure has been recognised as an important cardiovascular risk factor. The increase in pulse pressure with aging is mainly due to a decrease in large artery compliance. Compliance and distensibility are large artery wall properties. Compliance is the buffering capacity of the vessel. Distensibility reflects much more the elasticity of the artery. Compliance is related to distensibility and arterial diameter. These large artery wall properties can be measured non-invasively using new echo-tracking techniques. With these techniques it has been shown that the elasticity (distensibility) and the buffering capacity (compliance) of the common carotid artery is decreasing with aging, while diameter of the artery increases. This increase in diameter might be a compen-
Nicorandil (N) and isosorbide dinitrate (ISDN) are vasodilator drugs used in patients with angina. In 24 healthy male volunteers (18-32 years), the acute effect of a single oral dose (20 mg) of N and ISDN on arterial diameter (D), distensibility, and compliance of the elastic common carotid artery (CCA) and the muscular femoral (FA) and brachial (BA) arteries were investigated. The effects on systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), cardiac index (CI), systemic vascular resistance index (SVRI), and venous hemodynamics were also assessed. In addition, the subacute effects after 8 days of treatment with N (2 x 20 mg/day) and ISDN (3 x 20 mg/day) on these parameters were evaluated. After a 20 mg single oral dose, blood pressure decreased significantly more with ISDN (SBP: 6%; DBP: 14%) than with N (SBP: 2%; DBP: 6%), but after 8 days this decrease in blood pressure was not statistically different between ISDN and N. The diameter of CCA increased more with ISDN (11%) than N (5%) acutely as well as subacutely (ISDN: 12%; N: 9%). Heart rate increased only with ISDN (7% acutely, 3% subacutely). No differences between ISDN and nicorandil were found for acute and subacute effects on SVRI, venous hemodynamics, diameter of muscular arteries (FA, BA), and the distensibility and compliance of elastic (CCA) and muscular (FA, BA) arteries.(ABSTRACT TRUNCATED AT 250 WORDS)
Arterial compliance is found to be reduced in haemodialysis patients. It is not clear whether decreased arterial compliance in uraemic patients is a consequence of long-standing increased mean arterial blood pressure or a consequence of the uraemic state. An adequate blood pressure can be achieved by long-treatment-time dialysis of 8 h three times a week. We studied femoral and carotid artery wall properties in 24 normotensive patients on long-treatment-time dialysis and 24 normal controls matched for mean arterial pressure, age, sex, and body mass index. Arterial distensibility coefficient and compliance coefficient were determined with a vessel wall movement detector system, 24 h after dialysis in the supine position. The patients were 5.9 +/- 6.6 years on long-treatment-time dialysis at a Kt/V of 1.8 +/- 0.4. We found no significant differences in mean arterial pressure or pulse pressure between patients (85 +/- 13, 55 +/- 17 mmHg) and controls (84 +/- 6, 50 +/- 13 mmHg). Femoral distensibility coefficient and compliance coefficient were lower in patients (6.0 +/- 2.4 10(-3)/kPa; P < 0.05, 0.52 +/- 0.28 mm2/kPa; n.s.) compared to the controls (8.8 +/- 4.0 10(-3)/kPa, 0.67 +/- 0.38 mm2/kPa). No differences in carotid distensibility coefficient and compliance coefficient were found between patients (12.8 +/- 4.6 10(-3)/kPa, 0.72 +/- 0.30 mm2/kPa) and controls (14.1 +/- 4.4 10(-3)/kPa, 0.70 +/- 0.23 mm2/kPa). We conclude that patients on long-treatment-time-dialysis have an increased stiffening of the muscular femoral artery but not of the more elastic carotid artery. Results suggest that the uraemic state itself has a deleterious effect on the elastic properties of the muscular femoral artery.
The relative merits of sequential bypass grafting were compared to those of conventional bypass grafting in 247 patients undergoing uncomplicated coronary artery bypass graft surgery. The duration of both ischemic arrest and cardiopulmonary bypass could be predicted on the basis of the number of end-to-side and side-to-side anastomoses. Multivariate regression showed that sequential grafting can be executed more quickly than conventional grafting because: 1. the suture time for side-to-side anastomoses is less than that for end-to-side (5 vs. 12 min) and, 2. fewer aortic anastomoses are required. The rate of perioperative myocardial infarction was similar in both groups. In 109 patients recatheterized at one year, both groups improved equally in functional class, there was no significant difference in mortality, and graft patency was similar in both groups. The principal advantage of sequential grafting therefore is a shorter duration of ischemic arrest and cardiopulmonary bypass, while graft patency and the overall benefit of surgery remains the same.
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