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Biomedical subjects

D G Vidt

Publications and source records attributed to D G Vidt.

At least 19 recordsLinked to original sources
PubMed1991

The diagnosis of renovascular hypertension. A clinician's viewpoint.

The sensitivity and specificity of screening and diagnostic studies for renovascular hypertension has been the focus of debate and disappointment for many years. The use of these studies has been further restricted by the insistence of clinicians that studies provide visual identification of the anatomy of the renal vasculature. Digital subtraction angiography continues to provide an increasingly attractive alternative offering visualization of the renal arteries. Reevaluation of screening and diagnostic studies is needed to determine their potential value, particularly in patients with atherosclerotic renovascular disease and renal insufficiency and in assessing the potential salvability of the ischemic kidney.

Angiography, Digital Subtraction↗
PubMed1991

Calcium channel blockers in geriatric hypertension.

Though the calcium channel blockers have been used to treat angina pectoris for almost a decade, the long-acting forms of these agents that have become available in the last few years have made them practical for use as antihypertensive agents as well. They are becoming increasingly popular in this role, especially to treat elderly hypertensive patients. Because they are vasodilators with a mild diuretic action, they are logical treatment choices for the majority of hypertensive patients who have increased peripheral vascular resistance. They offer the advantage of a dual benefit for hypertensive patients with angina, and they have no effect on carbohydrate or lipid metabolism. Disadvantages include cost and a side effect profile that includes headaches, palpitations, ankle edema, and constipation.

Aged↗
PubMed1990

Comparison of labetalol and hydrochlorothiazide in elderly patients with hypertension using 24-hour ambulatory blood pressure monitoring.

The safety and efficacy of labetalol and hydrochlorothiazide (HCTZ) were compared in a group of 34 patients aged 65 years or older with mild to moderate essential hypertension. After a 4-week placebo run-in period, during which all previous antihypertensive medication was discontinued, patients were randomized to receive either labetalol (100 mg bid) or HCTZ (25 mg bid). The patients' blood pressure and heart rate were evaluated biweekly and drug dosage was titrated (up to 400 mg and 50 mg bid of labetalol and HCTZ, respectively) to achieve a standing diastolic blood pressure less than 90 mm Hg. Patients underwent 24-hour ambulatory blood pressure monitoring at the end of the placebo run-in period and again after the 6-week titration period. Both labetalol and HCTZ significantly (P less than .01) reduced standing systolic (-19.4 vs -27.7 mm Hg) and diastolic (-14.0 vs -15.2 mm Hg) blood pressures following 12 weeks of treatment. Both antihypertensives effectively controlled the 24-hour ambulatory blood pressure, however, the labetalol group experienced a significantly lower rate of rise in diastolic blood pressure (P = .02) and mean arterial pressure (P = .02) during the acceleration period (400-1200) compared to the HCTZ group. HCTZ caused significant decreases in serum potassium (P less than .01) and alkaline phosphatase (P less than .05) and increases in uric acid (P less than .01) and urea nitrogen (P = .07). These results indicate that labetalol may offer some unique advantages over thiazide diuretics that may be particularly important in the treatment of elderly patients with hypertension.

Aged↗
PubMed1989

Mechanism of antihypertensive action of dilevalol compared with that of "cardioselective" beta-blocking agents.

The hemodynamic effects of dilevalol, a nonselective beta-adrenergic blocking agent with vasodilating properties, were evaluated in 34 hypertensive patients and compared with those of the "cardioselective" beta blockers atenolol and metoprolol in 21 patients. Hemodynamic measurements were obtained at baseline, after acute treatment (first dose) with dilevalol (400 mg) and atenolol (50 mg) or metoprolol (100 mg), and again after subchronic treatment with these agents. After both acute and subchronic treatment (mean daily dose 1,042 mg), dilevalol significantly reduced mean arterial pressure (MAP, p less than 0.0001), by significantly reducing systemic vascular resistance index (SVRI, p less than 0.001), and by not significantly altering cardiac index (CI). In contrast, atenolol and metoprolol significantly reduced MAP (p less than 0.002) by significantly reducing CI (p less than 0.0001), with a concomitant increase in SVRI (p less than 0.007). Heart rate (HR) was reduced significantly less (p less than 0.006) with dilevalol than with the cardioselective agents. Correlation of the decrease in MAP with other hemodynamic parameters revealed that the effects on MAP of acute treatment with the cardioselective drugs are related to a decrease in HR (r = 0.63, p = 0.002), whereas those of subchronic treatment are correlated to a decrease in CI (r = 0.59, p = 0.01). The decrease in MAP after acute and subchronic dilevalol treatment is correlated primarily with SVRI (r = 0.46 to 0.49, p less than 0.01) and only secondarily with HR (r = 0.34, p less than 0.05). Therefore, the main mechanism of antihypertensive action for dilevalol is vasodilation, in contrast to the cardioselective agents, which is beta blockade.

Adult↗
PubMed1989

Celiprolol in systemic hypertension.

The safety and efficacy of orally administered celiprolol, a new beta 1-selective adrenergic blocking drug with peripheral beta 2-agonist properties, were assessed in 91 patients with mild to moderate systemic hypertension (supine diastolic blood pressure [BP] 95 to 114 mm Hg without medication) using a placebo-controlled, double-blind, randomized, titration-to-effect study design. All patients received placebo for 4 weeks and were then randomized to receive placebo (n = 46) or once-daily celiprolol (n = 45), which was titrated every 2 weeks (200, 400, 600 mg/day) over a 6-week period to achieve a reduction in supine diastolic BP to less than or equal to 90 mm Hg. Plasma lipids and lipoproteins were also assessed at baseline, during placebo and after randomization to active therapy in a subgroup of patients. Compared with placebo, celiprolol reduced supine and standing BP (reduction of supine BP -0.4/-2.1 mm Hg with placebo, -5.7/-6.4 with celiprolol, p less than 0.05; reduction of standing BP -1.7/-1.0 with placebo, -7.2/-4.9 with celiprolol, p less than 0.05). Supine heart rate was reduced by 6.8 beats/min with celiprolol compared with 2.0 beats/min with placebo (p less than 0.05). No differences were seen when the effects of placebo and celiprolol on plasma lipoproteins were compared. Celiprolol is a safe, effective and well tolerated once-daily antihypertensive drug and has no detrimental effects on plasma lipids.

Antihypertensive Agents↗
PubMed1989

The diagnostic dilemma: a clinician's viewpoint.

The prevalence of renovascular hypertension appears to be increasing, particularly in older patients with generalized arteriosclerosis, hypertension and impaired renal function. While clinical clues remain extremely useful in identifying patients at increased risk, older screening tests have been largely abandoned in favor of angiographic methods that provide visual identification of renal artery lesions. Renal scintigraphic techniques, with or without angiotensin-converting enzyme (ACE) inhibition, offer the potential for providing accurate measurements of renal function, and may be particularly useful in identifying critical renal arterial stenosis. In assessing the future role of scintigraphy, careful clinical validation of these correlations will be necessary, as will determinations of their usefulness in patients with renal insufficiency and those with bilateral renal artery stenosis. The role of adrenal scintigraphy in the localization of adrenal tumors is also reviewed. Their cost-effectiveness, limitations in sensitivity and specificity compared to current diagnostic technologies, and potential applications are discussed.

Adrenal Gland Neoplasms↗
PubMed1989

Reversal of end stage renal failure with surgical revascularization in patients with atherosclerotic renal artery occlusion.

A total of 9 patients with end stage renal failure caused by atherosclerotic renal artery occlusion underwent surgical revascularization with subsequent recovery of renal function. The duration of dialysis preoperatively ranged from 1 week to 13 months. In all cases renal viability was being maintained by collateral vascular supply. Postoperatively, renal function improved immediately and no patient required subsequent dialysis. Excellent over-all rehabilitation was achieved in all patients. Six patients currently are alive at a mean interval of 4.0 years postoperatively and with satisfactory renal function (mean serum creatinine 2.7 mg. per dl.). Three patients died at a mean interval of 6.8 years postoperatively and they all maintained satisfactory renal function (mean serum creatinine 3.0 mg. per dl.) until death. In some patients with end stage renal failure caused by atherosclerotic arterial occlusion surgical renal revascularization can yield extended survival with freedom from chronic dialysis.

Aged↗
PubMed1989

The safety of cumulative doses of labetalol in perioperative hypertension.

Intravenous labetalol is commonly used in the management of hypertensive emergencies or urgencies as well as postoperative hypertension. The maximum recommended dose in any clinical setting is 300 mg in 24 hours. The safety of administering high doses of intravenous labetalol (greater than 300 mg in 24 hours) was evaluated in neurosurgical patients (n = 9). During 15 distinct periods of 24 hours or less, the mean dose of labetalol given was 623 +/- 86 mg. Adverse hemodynamic and biochemical effects were minor and easily reversible. Intravenous labetalol can safely be used in doses exceeding 300 mg per 24 hours in neurosurgical patients.

Adult↗
PubMed1989

Atheroembolic renal disease: association with renal arterial stenosis.

In elderly patients with generalized atherosclerosis and longstanding hypertension, progressive renal insufficiency should suggest renal artery occlusive disease and/or renal cholesterol embolization. Renal cholesterol embolization is not an absolute contraindication to successful surgical revascularization. Renal cholesterol emboli were identified in biopsy specimens obtained in 24 cases at the Cleveland Clinic from 1978 to 1986, and renal artery stenosis was an associated finding in 19. Clinical manifestations of generalized atherosclerosis were common, including ileofemoral atherosclerosis (18), coronary artery disease (16), carotid occlusive disease (15), and carotid occlusive disease with a history of stroke (8). Evidence of embolic events in other organs was common. Hypertension worsened before biopsy in 21 patients with and without renal artery stenosis. Surgery or angiography definitely or probably contributed to renal failure in 16. Of 12 who underwent surgical revascularization of a renal artery, renal function improved in five, remained stable in five, and worsened in one. Renal function improved in the three patients undergoing dialysis before revascularization, and two were able to discontinue dialysis.

Aged↗
PubMed1989

Baseline renal function and surgical revascularization in atherosclerotic renal arterial disease in the elderly.

From 1975 to 1984, 107 patients greater than or equal to 60 years of age had surgical revascularization at the Cleveland Clinic for correction of atherosclerotic renal arterial disease. To evaluate the effect of baseline renal function (RF) on outcome in older patients, the patients were retrospectively divided according to their preoperative serum creatinine levels into Group I, less than or equal to 1.4 (N = 26), and Group II, greater than or equal to 1.5 (N = 81). Extrarenal atherosclerosis was more frequent in Group II (P less than .005). Higher rates of complications were seen both in Group II and with extrarenal atherosclerosis, but these associations did not achieve statistical significance (P = .07). Baseline RF did not affect results, but after revascularization, the fall in diastolic blood pressure was greater in Group I (28.2 +/- 4.4 mmHg v 17.4 +/- 1.8 mmHg, P less than .05). No such effect was noted in systolic blood pressure or in the frequency of cure or improvement v failure. Operative mortality for the entire group was 2.8%.

Arteriosclerosis↗
PubMed1989

Secondary renal revascularization for recurrent renal artery stenosis.

Six patients are presented who underwent secondary renal revascularization for recurrent renal artery stenosis. The initial pathologic diagnosis was fibrous dysplasia in three patients and atherosclerosis in three patients. All patients had initially undergone a successful aortorenal bypass operation. Recurrent renal artery stenosis and hypertension developed 11 to 120 months later (mean, 58 months). Secondary revascularization operations included renal autotransplantation (2 patients), hepatorenal bypass (2), iliorenal bypass (1), and aortorenal bypass (1). Hypertension was relieved, and renal function was stabilized or improved in all cases. If hypertension recurs after renal revascularization, a recurrent but correctable lesion should be suspected.

Adult↗
PubMed1989

Dilevalol in severe hypertension. A multicenter trial of bolus intravenous dosing.

Dilevalol, the R-R optical isomer of labetalol, a nonselective beta-antagonist with vasodilation from selective beta 2 agonism, was administered in sequential multiple bolus intravenous injections of 10 to 100 mg in total doses ranging from 35 to 585 mg (mean dose, 414 mg) to 101 patients with supine diastolic blood pressures above 120 mm Hg. Mean blood pressure was reduced from 200 (+/- 3)/129 (+/- 1) mm Hg to 149 (+/- 2)/101 (+/- 1) mm Hg, a mean reduction of 51/28 mm Hg. The therapeutic goal was established as a reduction in supine diastolic blood pressure to less than 100 mm Hg or a reduction of at least 30 mm Hg. This was achieved in 62 (61%) of 101 patients, with an additional 7 patients having a final supine diastolic blood pressure of 100 mm Hg. Treatment with dilevalol was less successful in black male patients than in the group at large. There was a tendency for older patients to respond better than younger patients. Prior recent treatment of patients with beta-adrenergic antagonists decreased the effectiveness of the drug. Significant orthostatic hypotension was not noted. Sixty-four patients were transferred to oral dilevalol treatment in combination with a diuretic, and blood pressure in this group averaged 160/100 mm Hg after 1 month of therapy. Dilevalol appears to be a safe and effective drug that can be used intravenously successfully in the majority of patients with severe hypertension and provides an alternative to therapy with other agents. It also is a useful agent for oral treatment of these patients after successful intravenous therapy.

Administration, Oral↗
PubMed1988

Experience with percutaneous transluminal angioplasty for renal artery stenosis at the Cleveland Clinic.

From April 1979 to June 1985 percutaneous transluminal angioplasty was attempted in 68 patients at our clinic to treat renovascular hypertension and/or to preserve renal function. The etiology of renal artery disease was atherosclerosis in 55 patients, fibrous dysplasia in 6, renal transplant arterial stenosis in 5 and postoperative saphenous vein graft stenosis in 2. A successful clinical outcome, defined as a decrease in blood pressure and/or improvement in renal function, was achieved in 12 patients (26.1 per cent) with atherosclerotic renal artery disease, 3 (75 per cent) with fibrous dysplasia, 2 (100 per cent) with saphenous vein graft stenosis and all 5 with transplant renal arterial stenosis (100 per cent). Improved results were observed in patients with nonostial atherosclerotic lesions compared to ostial lesions. There were 23 complications (33.8 per cent) after percutaneous transluminal angioplasty and all but 1 occurred with atherosclerosis. Of these complications 13 (19 per cent) were considered major. Since the beginning of 1983, however, only 3 complications occurred among 32 procedures (9.4 per cent) and only 1 of these was of major significance. When technically feasible, percutaneous transluminal angioplasty can provide effective treatment for selected patients with renal artery stenosis.

Angioplasty, Balloon↗
PubMed1988

Labetalol to control blood pressure after cerebrovascular surgery.

Fifteen patients who had undergone neurovascular surgery for arteriovenous malformations or cerebrovascular aneurysms and had intracranial pressure (ICP) monitors were studied. The patients had been treated initially with sodium nitroprusside to maintain their arterial BP in a prescribed range, but, because of excessive nitroprusside dose requirements, they were considered either to have refractory BP or to be at risk for thiocyanate toxicity. Intravenous labetalol therapy was started either by frequent bolus pulse therapy every 1 to 2 h or by continuous infusion therapy. The degree of desired arterial BP control and the effects on ICP and cerebral perfusion pressure (CPP) were assessed and compared with the results during nitroprusside therapy. The degree of arterial BP control with labetalol was assessed to be good; 11 patients were weaned off nitroprusside and the remaining four patients had a substantial reduction in their nitroprusside requirements, needing an average of only 1.5 micrograms/kg.min of nitroprusside to control their BP compared with average requirements of 10 micrograms/kg.min of nitroprusside before labetalol therapy. Labetalol therapy improved CPP in six patients and ICP in five patients, with no significant change in cerebral pressure in the remainder. Overall, the CPP in the 15 patients improved from 63 +/- 15 (SD) mm Hg with nitroprusside to 65 +/- 10 mm Hg with labetalol therapy and the ICP decreased from 11.3 +/- 6.1 mm Hg with nitroprusside to 8.6 +/- 3.1 mm Hg with labetalol therapy (p less than .05 by Wilcoxon matched pairs).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Clinical implications of primary aldosteronism with resistant hypertension.

Twenty-eight patients with resistant hypertension were found to have primary aldosteronism; 25 had solitary adenoma and 3 had adrenal hyperplasia. All were severely hypertensive despite receiving three or more antihypertensive agents, including conventional doses of diuretics, sympatholytics, and vasodilators. Hypervolemia (24 patients) or normovolemia (2 patients) despite severe diastolic hypertension was the hallmark in 26 patients. Adequate salt and water depletion alone with spironolactone (200 mg/day) and hydrochlorothiazide (50-100 ng/day) reduced arterial pressure in all. Twenty-two patients had surgical removal of a solitary adenoma. Over 1 to 2 years of follow-up, 13 were normotensive without medication, and six required hydrochlorothiazide and three hydrochlorothiazide plus a beta-blocker to normalize blood pressure. Blood pressure response to surgery had no relation to either duration or severity of hypertension. Six patients (three with hyperplasia, three with adenoma) have continued diuretic therapy and are normokalemic and normotensive. These results indicate that primary aldosteronism can be associated with sever and drug-resistant hypertension, that maintained hypervolemia is the reason for resistance to therapy, that sustained volume depletion is the most important therapeutic goal for these patients, and that cure can be achieved despite prolonged and severe hypertension.

Adenoma↗
PubMed1988

The patient with resistant hypertension. Cations, volume, and renal factors.

Hypertension that is truly resistant to modern antihypertensive therapy is uncommon. In the majority of cases, apparent resistance is more likely associated with poor patient adherence, interacting drugs, drug interactions, and inappropriate drug dosages. Sodium and fluid volume play a major role in resistant hypertension. There is considerable evidence to support the role of dietary sodium restriction in successful nonpharmacological treatment of hypertension. Salt sensitivity in humans appears to represent at least one factor determining individual susceptibility to variable salt intakes. Sodium and water retention may lead to refractoriness to many antihypertensive agents, and there is evidence to suggest that extracellular fluid volume expansion also plays a role in many hypertensive patients. While retention of sodium and water is well established early in patients with renal parenchymal disease, hypertension associated with progression of renal parenchymal disease is complicated by other factors that include interactions between hemodynamic and humoral factors, functional changes in adrenergic responses, and structural vascular disease. The role of other cations such as potassium, calcium, and magnesium in resistant hypertension has yet to be established.

Drug Resistance↗
PubMed1988

Captopril-induced cough.

Since the advent of angiotensin-converting enzyme inhibitors (captopril and enalapril), cough has been recognized sporadically as a side effect, but has received little attention in the pulmonary literature. To emphasize that angiotensin-converting enzyme (ACE) inhibitors should be considered among possible etiologies of cough, we report recent experience with two patients and review the available experience with ACE inhibitor-induced cough.

Captopril↗