Optimal antihypertensive therapy for prevention and treatment of left ventricular hypertrophy.

Left ventricular hypertrophy (LVH) is considered an adaptation to a pressure load on the left ventricle and is common in hypertensive patients. The condition is a profound risk factor for cardiovascular events, greater than and independent of blood pressure. It is now recognized in hypertension management guidelines as an indication for more stringent blood pressure control. All of the first-line antihypertensive agents have been shown to variably regress LVH, but no definitive evidence yet shows that one agent is superior to others in decreasing risk independent of blood pressure control. Although some evidence suggests that reduction of LVH is associated with improved prognosis independent of blood pressure control, relative efficacy of drug classes in this regard has yet to be demonstrated. At present, recommendations for optimal therapy in hypertensive patients with LVH must rest on the presence of underlying cardiac and noncardiac conditions, with the understanding that the major classes of antihypertensive agents will probably decrease LVH.

Effect of a femoral arteriovenous fistula on lower extremity venous hemodynamics after femorocaval reconstruction.

PURPOSE: To study the hemodynamic effects of an arteriovenous fistula (AVF) used as an adjunct to venous reconstructions and to determine the optimal size for such a fistula. METHODS: A model of limb circulation with an AVF (in vitro system) was constructed with silicon elastic tubes and 40% glycerin solution as the fluid medium. Pulsatile arterial flow and venous return was maintained with a roller pump and a centrifugal assist device. Flows and pressures were measured for three different fistula diameters (3, 4, and 5 mm). A canine model of venous hypertension with outflow obstruction was constructed in 15 adult mongrel dogs. After 7 to 13 days an externally supported 8-mm expanded polytetrafluoroethylene femorocaval graft was implanted with a distal AVF (3 mm, n = 5; 4 mm, n = 5; 5 mm, n = 5). Arterial and venous flows and venous pressures were measured proximal and distal to the fistula before and after exercise. RESULTS: In the in vitro system, flows through the venous graft increased with increasing fistula size, but venous return decreased progressively, increasing the distal venous pressure. In the canine model, flow in the venous graft increased with each AVF (p < 0.01). Only the 3-mm AVF resulted in decreased distal femoral vein pressure (p < 0.01), orthograde flow, and improved venous return with exercise. CONCLUSION: AVFs increased flow through the femorocaval grafts, yet they impeded venous return. The ideal AVF-to-graft ratio used in our study was 0.375, because it increased graft flow, permitted forward flow in the femoral vein while reducing pressure, and improved venous return with exercise.

Mesenteric venous thrombosis: still a lethal disease in the 1990s.

PURPOSE: This study was designed to evaluate progress in diagnosis, management, and clinical outcome of mesenteric venous thrombosis (MVT). METHODS: We retrospectively reviewed the clinical course of 72 patients treated for mesenteric venous thrombosis between 1972 and 1993. RESULTS: Fifty-three patients had acute and 19 had chronic mesenteric venous thrombosis. Fifty-seven patients had secondary mesenteric venous thrombosis; previous abdominal surgical procedure and hypercoagulable states were the most prevalent associated conditions. Computed tomography was abnormal in all patients who underwent this test for acute mesenteric venous thrombosis and in 93% of those who had chronic disease. Angiography diagnosed acute mesenteric venous thrombosis in five (72%) of seven patients. Acute mesenteric venous thrombosis presented most frequently as abdominal pain (83%), anorexia (53%), and diarrhea (43%). Thirty-three (75%) had symptoms longer than 48 hours. Thirty-four (64%) patients with acute mesenteric venous thrombosis underwent a surgical procedure. Bowel resection was necessary in 31 patients. One patient had unsuccessful mesenteric venous thrombectomy. Seven patients with acute mesenteric venous thrombosis underwent anticoagulation without a surgical procedure, and 12 were observed. All patients with chronic mesenteric venous thrombosis were observed; nine of the 19 underwent anticoagulation. The median delay in diagnosis for patients with acute mesenteric venous thrombosis was 48 hours and did not decrease during the last decade. Mesenteric venous thrombosis recurred in 19 (36%) patients. The 30-day mortality was 27%. Long-term survival of patients with acute mesenteric venous thrombosis was significantly worse than that of those with chronic disease (36% vs 83% survival at 3 years). The patients with acute mesenteric venous thrombosis who underwent anticoagulation with and without surgical procedure had improved survival when compared with the observed group. CONCLUSION: Acute mesenteric venous thrombosis remains a lethal disease. Mortality has not improved in the last 22 years. Computed tomography is the most sensitive diagnostic test. Anticoagulation and surgical procedure enhanced survival in the acute subgroup. The underlying disease determined survival in chronic disease.