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Biomedical subjects

A Schirger

Publications and source records attributed to A Schirger.

At least 19 recordsLinked to original sources
PubMed2000

Outcomes of atherosclerotic renal artery stenosis managed without revascularization.

OBJECTIVE: To determine how often patients with renal artery stenosis (RAS) managed without revascularization progress to accelerated hypertension and/or renal failure. PATIENTS AND METHODS: We examined the outcomes of 68 patients (mean +/- SEM age, 71.8 +/- 0.9 years) with high-grade (>70%) RAS identified between 1989 and 1993 who were treated without renal revascularization for at least 6 months after angiography. The time to last follow-up averaged 38.9 +/- 2.8 months. Other vascular beds were affected in 66 of the 68 patients. End points were revascularization, nephrectomy, dialysis, or death. RESULTS: The mean +/- SEM serum creatinine level rose from 1.4 +/- 0.1 to 2.0 +/- 0.2 mg/dL (P<.001). Mean +/- SEM blood pressure did not change (157 +/- 3/83+/-2 vs 155 +/- 3/79 +/- 2 mm Hg), but the need (mean +/- SEM) for medication increased from 1.6+/-0.1 to 1.9+/-0.1 drugs (P=.02). Four patients (5.8%) eventually underwent renal revascularization for refractory hypertension (1 patient), for progressive stenosis (1 patient), and during aortic reconstruction (2 patients). One additional patient underwent nephrectomy to improve blood pressure control. Five others (7.4%) developed end-stage renal disease (ESRD) for reasons other than progressive vascular disease, namely, diabetes (3 patients), atheroemboli (1 patient), and contrast toxicity without RAS progression (1 patient). In 1 further case, the reason for ESRD was unknown, and it may have been caused by vascular occlusion. During follow-up, 19 patients died of unrelated causes, including myocardial infarction and stroke. CONCLUSIONS: These data indicate that antihypertensive medication requirements increased and renal function deteriorated modestly in a subset of patients with atherosclerotic RAS managed initially without vascular intervention. Many achieved stable blood pressure for many years. Deterioration of renal function and mortality risk were greatest in patients with bilateral stenosis or stenosis to a solitary functioning kidney. These results reinforce the need for meticulous follow-up for disease progression but underscore the role of competing risks and high mortality from other cardiovascular diseases, which primarily determine the outcomes in patients with RAS and widespread atherosclerotic disease.

Aged↗
PubMed1995

Renal artery angioplasty: technical results and clinical outcome in 320 patients.

OBJECTIVE: To review the results of percutaneous transluminal renal artery angioplasty (PTRA), including technical success and clinical outcome, at Mayo Clinic Rochester. DESIGN: We retrospectively reviewed our experience with 320 patients who underwent PTRA for stenosis of 396 arteries during a 14-year period. MATERIAL AND METHODS: We reviewed medical records and angiograms of patients who underwent PTRA at Mayo Clinic Rochester between January 1980 and December 1993. The patients were divided into four groups, based on clinical history and angiographic appearance of the stenosing lesion: renal artery atherosclerosis (ASO group), fibromuscular dysplasia (FMD group), previous renal artery bypass or endarterectomy, and renal artery stenosis in a solitary kidney. Technical results of the PTRA were determined by evaluation of angiograms obtained before and after the procedure. Data on patient demographics, blood pressure, antihypertensive medications, and serum creatinine were recorded for the period preceding PTRA, after the procedure, and at last follow-up. RESULTS: All groups had statistically significant reductions in mean arterial pressure and antihypertensive medications after PTRA. The percentage of patients who benefited after renal artery angioplasty was 70% for patients with ASO (8.4% cured), 63% for patients with FMD (22% cured), 53.8% for patients with prior surgical revascularization (23.1% cured), and 91.7% for patients with a solitary kidney (0% cured). No significant overall change in serum creatinine level was noted after the procedure in any group. Complications were comparable to those reported in other studies. The 30-day all-cause mortality rate was 2.2% for the current study, all deaths occurring in the ASO group. CONCLUSION: PTRA rarely leads to a "cure" of renovascular hypertension but provides effective control of blood pressure and decreases the medication requirements in selected patients.

Adult↗
PubMed1993

Cervicothoracic sympathectomy for Raynaud's syndrome.

Raynaud's syndrome is a clinical entity characterized by episodic vascular spasm and digital ischemia occurring in response to cold or emotional stimuli. Most patients with Raynaud's syndrome are successfully managed with medical therapy. Surgical sympathectomy is rarely performed and its use remains controversial. Of 3,219 patients seen with the diagnosis of Raynaud's disease, phenomenon or syndrome over the last 10 years at Mayo Clinic, 20 cervical or thoracic sympathectomies were performed in 14 (0.4%) patients. Of all patients who underwent cervico thoracic sympathectomy (68) for various reasons during the same time period, 20.5% (14/68) were performed for Raynaud's syndrome. Surgical sympathectomy was reserved for those rare patients with persistent, severe symptoms (pain, ulcer) despite intensive medical treatment. Surgical therapy was also used for those few patients with occupations involving exposure to cold and disabling, refractory symptoms in hopes of allowing them to return to work. Transaxillary (12 limbs) or supraclavicular (8 limbs) exposure and resection of the sympathetic chain with T1-T4 ganglions was usually performed. Initial resolution or improvement of symptoms was achieved in 19/20 (95%) of limbs. Both patients with digital ulceration healed. Although improved in some, persistent or recurrent symptoms were present in all patients after six months postoperatively. Increased sensitivity of digital vessels to circulating catecholamines, nerve fiber regeneration or incomplete sympathectomy have been postulated to lead to recurrence. Five patients developed Horner's syndrome postoperatively. A portion of the stellate ganglion was intentionally resected in 3 of the 5 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

HN-10200 causes endothelium-independent relaxations in isolated canine arteries.

HN-10200, a nonselective inhibitor of phosphodiesterase, has positive inotropic and vasodilator activity. The present study was designed to determine the role of endothelium in causing relaxation to HN-10200 in isolated canine femoral and basilar arteries. Rings with and without endothelium were suspended for isometric tension recording in Krebs-Ringer bicarbonate solution bubbled with 94% O2, 6% CO2 (t = 37 degrees C; pH = 7.4). HN-10200 and another nonselective phosphodiesterase inhibitor, 3-isobutyl-1-methyl-xanthine (IBMX), caused similar concentration-dependent relaxations in femoral arteries with and without endothelium. In femoral arteries without endothelium, HN-10200 and IBMX significantly augmented relaxations to prostacyclin, but did not affect relaxations to a nitric oxide donor 3-morpholinosydnonimine (SIN-1) or endothelium-derived relaxing factor (EDRF) released by bradykinin. In basilar arteries, relaxations to HN-10200 were augmented by the removal of endothelium, whereas relaxations to IBMX were not affected. Relaxations to prostacyclin, SIN-1, and EDRF were not affected by the presence of phosphodiesterase inhibitors. The results of the present study suggest that HN-10200 causes endothelium-independent relaxations. In addition, it may augment relaxations to prostacyclin but does not affect relaxations to EDRF.

1-Methyl-3-isobutylxanthine↗
PubMed1990

Antihypertensive effects of a new sustained-release formulation of nifedipine.

The blood pressure response to a new sustained-release formulation of nifedipine was evaluated in an 8-week, double-blind, placebo-controlled study. Twenty-nine patients with mild essential hypertension were randomized to receive placebo (N = 9), 30 mg nifedipine (N = 10), or 60 mg nifedipine (N = 10). During treatment, 30-mg and 60-mg doses of nifedipine administered once daily decreased office blood pressures from 137/98 +/- 8/2 mm Hg and 141/98 +/- 15/2 mm Hg at baseline, respectively, to 126/89 +/- 9/7 mm Hg and 126/86 +/- 6/7 mm Hg (P less than .005). Noninvasive automatic ambulatory blood pressure monitoring demonstrated a marginally significant (P less than .10) reduction in the mean 24-hour blood pressure of 2/6 +/- 8/8 mm Hg and 5/6 +/- 9/9 mm Hg for patients taking 30 mg and 60 mg nifedipine once daily, respectively. Diastolic blood pressure load (the percentage of ambulatory diastolic blood pressure readings greater than 90 mm Hg) during 24 hours was decreased by 41% and 35%, with 30 mg and 60 mg nifedipine administered once daily, respectively. No significant dose response to nifedipine at these dose levels was observed. Although the once-daily formulation of nifedipine achieved effective control of office blood pressure, similar control was not observed in awake and 24-hour periods in all patients.

Adult↗
PubMed1989

Noninvasive evaluation of the swollen extremity: experiences with 190 lymphoscintigraphic examinations.

Lymphoscintigraphy (LS), performed with technetium 99m-labeled antimony trisulfide colloid (Cadema Medical Products, Inc., Middletown, N.Y.), was used as a noninvasive diagnostic examination to evaluate the lymphatic circulation in 190 extremities of 115 patients. Forty-six patients had primary lymphedema, 48 had secondary lymphedema, and 21 patients had other causes of limb swelling. To determine the value of LS in surgical decision making, preoperative and postoperative LS of 16 patients who underwent surgical repair of the lymphatic abnormality were studied separately. Semiquantitative evaluation of the lymphatic drainage and visual interpretation of the image patterns were reliable to differentiate lymphedema from edemas of other origin (sensitivity: 92%, specificity: 100%). Although certain image patterns were characteristic of either primary or secondary lymphedema, LS could not consistently differentiate between the two types. Episodes of cellulitis in lymphedema clearly delayed lymph transport. LS was helpful in patient selection and follow-up after lymphatic surgery, but it did not prove patency of lymphovenous anastomoses. It was diagnostic in the evaluation of lymphangiectasia and was used to document successful surgical treatment of reflux of chyle. LS is safe and reliable and has no side effects. It should replace contrast lymphangiography in the routine evaluation of the swollen extremity.

Adolescent↗
PubMed1988

Correlation between verapamil plasma concentration and P-R prolongation in essential hypertension.

Plasma verapamil concentration was correlated with serial electrocardiographic P-R intervals in patients with essential hypertension receiving immediate-release (80 to 120 mg three times a day) or sustained-release (240 mg daily) verapamil. The mean P-R interval in 22 patients taking placebo and immediate-release verapamil was 0.18 second. The borderline first-degree atrioventricular block of three patients did not change during treatment. Plasma verapamil concentrations of patients with a P-R interval longer than 0.20 second and of those with a P-R interval of 0.20 second or less were 169 +/- 73 ng/mL and 63 +/- 8 ng/mL, respectively. Six patients taking sustained-release verapamil had a maximal mean P-R interval of 0.19 +/- 0.01 second during 24-hour ambulatory electrocardiographic monitoring. P-R intervals were 0.22 second or more in two patients, but they returned to normal by hour 7 for one and by hour 20 for the other patient. In summary, transient P-R prolongation occurred with oral verapamil therapy, but no patient, regardless of baseline P-R interval, developed high-grade atrioventricular block.

Delayed-Action Preparations↗
PubMed1988

Microsurgical lymphovenous anastomosis for treatment of lymphedema: a critical review.

Lymphovenous anastomoses (LVA) offer ideal physiologic treatment for lymphedema, and our experimental data support late patency. Between Jan. 1, 1982, and April 1, 1986, 18 patients underwent operation for chronic lymphedema; LVA could be performed in 14 patients (10 women and four men). Six patients had secondary lymphedema of the upper extremity. One of eight patients with lymphedema of the lower extremity had filariasis, and seven had primary lymphedema. Mean follow-up was 36.6 months (range: 5 to 57 months). Limb circumference and volume, number of postoperative episodes of cellulitis, and lymphoscintigraphy were used to assess results. Improvement occurred in three upper extremities and two lower extremities. There was no change in five extremities, and in four patients the edema progressed. One patient with primary lymphedema and four of seven patients with secondary lymphedema improved. Only one of five patients benefited from one anastomosis; however, all patients with more than two anastomoses improved. Lymphoscintigraphy was performed in 10 patients. No lymphatic channel was visualized before operation in three patients, and at operation none was found. In four other patients lymph channels localized by lymphoscintigraphy were identified during operation. Significant improvement was documented by lymphoscintigraphy in one patient after operation, and this patient had permanent improvement 30 months later. Patients with primary lymphedema had disappointing results, but four of seven patients with secondary lymphedema benefited from LVA, especially if several anastomoses could be performed. Lymphoscintigraphy appears to be a suitable method of both identifying patent lymph channels before surgery and determining function of LVA after operation. However, presently objective data to prove the clinical efficacy of this operation are lacking.

Adult↗
PubMed1988

Antihypertensive efficacy of lisinopril. Ambulatory blood pressure monitoring.

Noninvasive automatic ambulatory blood pressure monitoring during 24 hours in eight patients with moderate hypertension was used to determine the blood pressure response to lisinopril, an angiotensin-converting enzyme inhibitor. Office, 24-hour ambulatory, awake ambulatory, and sleep ambulatory diastolic blood pressures were decreased from 108 +/- 3, 98 +/- 8, 101 +/- 7, and 87 +/- 14 mm Hg, respectively, at baseline to 83 +/- 4 (P less than or equal to 0.0001), 82 +/- 7 (P less than 0.0001), 84 +/- 7 (P less than 0.0001), and 73 +/- 9 mm Hg (P less than 0.005), respectively, after 20 weeks of lisinopril treatment (dose range, 40 to 80 mg once daily). The diastolic blood pressure loads (percentages of ambulatory diastolic blood pressures more than 90 mm Hg) during 24 hours and during awake hours were 74% +/- 19% and 83% +/- 15%, respectively, at baseline and 24% +/- 19% (P less than 0.0001) and 29% +/- 21% (P less than 0.0001), respectively, during treatment. Heart rate was not altered by lisinopril. In conclusion, lisinopril is an effective antihypertensive agent for the treatment of moderate hypertension, and ambulatory blood pressures and diastolic blood pressure loads are useful for evaluating therapy for hypertension.

Adult↗
PubMed1987

Antihypertensive efficacy of sustained-release verapamil.

The antihypertensive effects of immediate-release (IR) verapamil were compared with those of sustained-release (SR) verapamil in 58 patients. After an open-label (IR verapamil) study, patients were randomized into a double-blind study to continue receiving the same dose of IR verapamil three times daily or an equivalent dose of SR verapamil (240 to 480 mg) once daily. Blood pressure decreased from 149/98 to 139/90 mmHg (p less than 0.01) with IR verapamil and from 150/98 to 136/88 mmHg (p less than 0.01) with SR verapamil. Ambulatory blood pressure monitoring showed a similar response for the two formulations. Diastolic pressure was less than 90 mmHg in approximately 67% of the IR verapamil group and 61% of the SR verapamil group. Mean trough plasma concentrations of verapamil were 70 and 59 ng/ml at 2 and 4 weeks, respectively, after treatment with IR verapamil; the corresponding values were 70 and 94 ng/ml for the SR verapamil group. SR verapamil administered once daily is an effective antihypertensive medication in a selected group of patients and could afford better compliance.

Blood Pressure↗
PubMed1987

Comparison of ketanserin and metoprolol in the treatment of essential hypertension.

Ketanserin, a serotonin receptor antagonist (S2), lowered blood pressure in patients with essential hypertension; at three months 72% (13/18) had a successful reduction in pressure. No marked orthostatic changes were noted. Older patients responded better when standing. Compared with metoprolol, ketanserin provided no significant difference in response at three months. With ketanserin, the heart rate was reduced only in the supine position, whereas it was reduced in the supine and standing positions with metoprolol. Response to ketanserin could not be predicted from baseline renin, aldosterone, or cortisol levels in blood, nor were there any changes in these factors or in plasma hydroxyindole levels with therapy. Ketanserin was generally well tolerated. Cholesterol values were significantly reduced with ketanserin, and there were no adverse hematologic or biochemical changes. Ketanserin should have a significant role in managing hypertension.

Blood Pressure↗
PubMed1986

Verapamil and 24-hour ambulatory blood pressure monitoring in essential hypertension.

The antihypertensive effects of oral regular and slow-release verapamil, a calcium-channel blocking agent, were evaluated in 22 patients with mild to moderate hypertension (sitting diastolic blood pressure [DBP] 95 to 112 mm Hg). The dose required to control blood pressure varied from 80 to 120 mg, 3 times a day. All patients received regular verapamil for a further 3 to 4 months, when systolic blood pressure (SBP) and DBP had risen from the end of the open-label phase. During a double-blind phase patients were randomly assigned to continue the same dose of regular verapamil, 3 times a day, or an equivalent daily dose of sustained-release verapamil (240 to 360 mg once a day). Seven of the 11 patients on regular and 3 of the 11 on sustained-release verapamil were also taking diuretics. This antihypertensive program was continued for at least 4 weeks. During the efficacy period, 24-hour ambulatory blood pressure monitoring was carried out. Mean 24-hour SBP and DBP were 133 +/- 20 and 89 +/- 13 mm Hg, respectively, on regular and 131 +/- 22 and 87 +/- 12 mm Hg, respectively, on sustained-release verapamil. There were no statistically significant differences noted between the 2 groups. Mean SBP and DBP varied similarly during awake and sleep hours with both formulations of verapamil. With regular verapamil, SBP was 139 +/- 18 and 124 +/- 20 mm Hg and DBP 92 +/- 11 and 84 +/- 13 mm Hg during awake and sleep hours, respectively; with sustained release, SBP was 138 +/- 21 and 122 +/- 22 mm Hg and DBP 92 +/- 10 and 80 +/- 10 mm Hg during awake and sleep hours, respectively. Heart rate fell during the entry period and continued during the entire study period. No other adverse effects were noted during the double-blind phase. In summary, verapamil is an effective antihypertensive medication and can be administered once a day as a sustained-release preparation; it is most useful in patients in whom adrenergic blocking drugs are indicated.

Administration, Oral↗
PubMed1986

Antihypertensive efficacy of pinacidil--automatic ambulatory blood pressure monitoring.

Forty-three patients with mild essential hypertension were randomized into two double-blind studies: pinacidil vs. placebo or pinacidil vs. hydralazine. Pinacidil (62 +/- 18 mg/day) decreased office systolic and diastolic blood pressures from 145 to 137 mm Hg and from 98 to 89 mm Hg, respectively, after 6 weeks of therapy. Similarly, hydralazine (128 +/- 28 mg/day) reduced supine systolic blood pressure from 140 to 134 mm Hg and supine diastolic blood pressure from 93 mm Hg to 84 mm Hg. Significant tachycardia was not noted with either drug. Ambulatory blood pressure was monitored for 24 h during the placebo-washout and efficacy phases with both pinacidil and hydralazine. Mean 24-h blood pressure was 128 systolic and 81 diastolic with pinacidil and 121 systolic and 76 diastolic with hydralazine. Reduction in awake hypertensive diastolic blood pressure was significant for both pinacidil and hydralazine. Normal sleep diastolic blood pressure was not reduced by pinacidil but was reduced by hydralazine. Side-effects with both drugs included edema, headache, and palpitations. These data demonstrate that pinacidil is as effective an antihypertensive agent as hydralazine.

Adult↗
PubMed1986

Pharmacodynamics of midodrine, an antihypotensive agent.

Midodrine is an orally active adrenergic agonist useful in the treatment of hypotension. We have investigated the pharmacodynamics of its active metabolite after oral midodrine therapy in nine patients with severe orthostatic hypotension. Peak plasma levels of the metabolite were reached in 60 to 90 minutes and ranged from 25 to 56 ng/ml. The mean values for distribution volume, plasma clearance, and t1/2 were 4.0 L/kg, 23 ml/min/kg, and 2.1 hours, respectively. Heart rate increased after 5 to 10 mg doses and the increases were statistically significant (P less than 0.05) at 120 minutes. An apparent increase in blood pressure was not statistically significant. The patients said that they felt better.

Administration, Oral↗
PubMed1986

Lymphoscintigraphy in lymphedema: an aid to microsurgery.

The role of lymphoscintigraphy, performed with 99mTc-labeled antimony sulfur colloid, in the diagnosis of lymphedema and as a test for selection of patients for microvascular operation was evaluated in 32 patients with primary and secondary lymphedema and four patients with other causes of leg edema. Lymphoscintigraphy clearly demonstrated if edema was of lymphatic origin. Five different image patterns were identified; abnormal image patterns could not be predicted from clinical history or physical findings. Quantitative evaluation of removal of the radioactive colloid from the injection site and appearance in lymph node sites and liver was of limited usefulness. Nine patients underwent various surgical procedures before or after lymphoscintigraphy. Lympho-venous anastomoses were possible only in patients who had patent lymph channels visible on lymphoscintigrams. Based on initial experience, lymphoscintigraphy seems to be useful to select patients for microvascular operation.

Adolescent↗
PubMed1985

Evaluation of pindolol dosage in hypertension by automatic indirect BP monitoring.

Pindolol, a nonselective beta-adrenergic blocking drug, lowered systolic and diastolic BP equally well during once-daily and twice-daily dosage. Side effects were few. Absence of supine bradycardia distinguished this drug from other beta-adrenergic blockers and likely was attributable to the agent's intrinsic sympathomimetic activity. Blood pressure variability was less during therapy. Automatic indirect BP monitoring reliably confirmed office and home BP recordings and indicated good control throughout waking and sleeping periods.

Adult↗
PubMed1985

Primary lymphedema in children and adolescents: a follow-up study and review.

Primary lymphedema, a disorder causing persistent swelling in an extremity, is rare in children and adolescents; it affects 1.15/100,000 persons less than age 20 years. It primarily affects girls near menarche. The records of 125 children and adolescents, aged 0 to 20 years, who were examined at the Mayo Clinic were analyzed; 99 of these patients were contacted to obtain follow-up data. The influences of estrogen and inflammation are thought to be important etiologic factors in primary lymphedema. The diagnosis can be made on the basis of a thorough history and physical examination. Lymphangiograms, venograms, and biopsies add nothing to the diagnosis because of the low incidence of tumor in children and adolescents. Conservative treatment is recommended: a Jobst-type stocking, elevation, and proper foot care. Diuretics are not recommended. Careful psychologic counseling, especially in adolescents, is highly recommended.

Adolescent↗