Survey of expectations among clients of three small animal clinics.

A questionnaire completed by 319 clients of 3 small animal clinics asked what clients expected and what they received in their interaction with the veterinarian. The survey emphasized communication and rapport established by the veterinarian. Client satisfaction was more highly correlated with how the owner was treated than how the pet was treated.

Angiotensin-converting enzyme inhibitors: are they all alike?

Although dissimilar in chemical structure and pharmacokinetics, the two available angiotensin-converting enzyme inhibitors captopril and enalapril have proved to be comparably effective in controlling essential and renal forms of hypertension in studies of once and twice daily dosing. Abundant data from controlled clinical trials and worldwide experience, particularly for captopril, indicate the safety and absence of subjective side effects when used alone in relatively low dosage or in combination with a diuretic.

The modified staple capsulorrhaphy for the correction of recurrent anterior dislocation of the shoulder.

Recurrent anterior dislocation of the shoulder is a fairly common disorder for which numerous surgical procedures have been described. This paper reviews 22 patients treated between 1970 and 1983 by a modified staple capsulorrhaphy. It describes the surgical technique and demonstrates an instrument designed to hold and aid the insertion of the staple. There were no major complications in using this technique. All patients had some restriction of external rotation after operation but no patient suffered a further dislocation during a long-term follow-up of 6.4 years on average.

The captopril test for identifying renovascular disease in hypertensive patients.

To develop a screening test for identifying renovascular hypertension, the blood pressure and plasma renin activity responses to an oral test dose of captopril were studied in 246 quietly seated hypertensive patients. The following criteria were developed that exploit the hyperresponsiveness of renin secretion in renovascular hypertensive patients: a 60-minute post-captopril plasma renin activity of 12 ng/ml per hour or more and an absolute plasma renin activity increase of 10 ng/ml per hour or more, along with a 150 percent increase in plasma renin activity (or a 400 percent increase if the baseline plasma renin activity was below 3 ng/ml per hour). Retrospectively, the test identified, among 200 hypertensive patients without evidence of renal dysfunction, all 56 patients with proved renovascular disease. In this group, false-positive results occurred only in two of 112 patients with essential hypertension and in six with secondary hypertension. Nine untreated patients had blood pressure levels of less than 160/100 mm Hg. The test was neither as sensitive nor specific in the 46 patients with renal insufficiency. This study demonstrates that the renin response to oral captopril is a useful screening test for identifying patients with unilateral or bilateral renovascular disease. Since the test also characterizes the renin dependency of the hypertension, it may have other diagnostic and therapeutic uses.

Indication for intervention in patients with renovascular hypertension.

It is now possible to accurately identify patients with renovascular hypertension who need renal angioplasty or revascularization. Evaluation does not require hospitalization and begins with the determination of an ambulatory plasma renin activity (PRA) indexed against sodium excretion and a captopril test. Subsequently differential renal vein renins with matching inferior vena caval (IVC) renins are measured often with converting enzyme inhibition. Identifying criteria are as follows: (1) high PRA indexed against sodium excretion, (2) hypersecretion of renin following captopril administration, (3) absence of renin secretion from the contralateral kidney, and (4) an ipsilateral renal vein renin increment at least 50% greater than the matching IVC renin. Patients who meet the criteria are admitted for percutaneous transluminal renal angioplasty.

Clinical evaluation of renovascular hypertension and therapeutic decisions.

The renal arteriogram alone, useful as an anatomic guide for the surgeon or radiologist, is inadequate to predict potential blood pressure reversal by correction of the obstructing lesion. A patient must be identified as having functionally significant renal arterial disease before intervention can be recommended. The authors discuss uncovering functionally significant renal artery stenosis, the pathophysiology of experimental Goldblatt hypertension, and criteria to identify renovascular hypertension, including peripheral plasma renin activity and differential renal-vein renin determinations.

The current role of renal angioplasty in the treatment of renovascular hypertension.

Percutaneous transluminal renal angioplasty, a relatively noninvasive technique, has assumed an increasing role in the treatment of renovascular hypertension. The combined advent of digital subtraction angiography, renal-vein renin samples, and percutaneous transluminal angioplasty have prompted many physicians to reassess their treatment strategies. The authors present their experience with renal angioplasty at the New York Hospital and briefly describe the history and mechanism of action of this procedure.

Hormonal and metabolic effects of angiotensin converting enzyme inhibitors. Possible differences between enalapril and captopril.

Inhibitors of angiotensin converting enzyme block the conversion of angiotensin I to angiotensin II, the active hormone of the renin-angiotensin system. This inhibition leads to a reduction in angiotensin-mediated vasoconstriction and aldosterone production. Although converting enzyme inhibitors have other potential metabolic effects, their beneficial effects in hypertension and congestive heart failure appear to be, in large part, related to their ability to reduce angiotensin II. This causes an increase in plasma renin levels and a fall in plasma and urine aldosterone, which can be sustained for many years. As a consequence, converting enzyme inhibitors produce mild natriuresis and positive potassium balance. At conventionally used doses, enalapril more completely prevents posture-induced increases in aldosterone than does captopril, probably reflecting more complete inhibition of angiotensin II formation in vivo.

Predictive value and changes of renin secretion in hypertensive patients with unilateral renovascular disease undergoing successful renal angioplasty.

Peripheral and renal vein renin activity was measured in 46 hypertensive patients with arteriographically diagnosed unilateral renal artery stenosis before and six months after technically successful renal angioplasty. The renin-sodium profile was high in 80 percent before angioplasty, fell in all patients, and became normal or low in 85 percent after angioplasty. Renal vein renin activity, which initially showed lateralization of renin secretion to the ischemic kidney with contralateral suppression, became normal. Renal vein renin activity was more reliable for predicting the therapeutic response when expressed as the increment of renin for each renal vein over the infrarenal vena caval value (sensitivity 74 percent, specificity 100 percent) than as the ratio between the two renal veins (sensitivity 62 percent, specificity 60 percent). The predictive value of renal vein renin activity is poor when plasma renin activity is stimulated by long-term administration of captopril. These data support the usefulness and define the limitations of peripheral and renal vein renin measurements in selecting patients for treatment by renal angioplasty.

Converting enzyme inhibition to identify and treat renin-mediated or sodium-volume related forms of increased peripheral resistance in hypertension and in congestive heart failure.

Ten years of experience with three different converting enzyme inhibitors (CEI; teprotide, captopril and enalapril) in over 300 hypertensive patients reveals that CEI act largely to block renin-angiotensin mediated vasoconstriction. Thus, their effectiveness or lack of it is predicted by the baseline plasma renin measurement. Accordingly, responses to these pharmacological agents can be used to identify and quantify renin-mediated vasoconstriction in the spectrum of hypertensive diseases. The converse is also generally true. Patients failing to respond to CEI exhibit low renin values and their increased peripheral resistance appears related to other mechanisms, possibly involving a subtle increase in total body sodium. Thus, low renin states such as low-renin essential hypertension, primary aldosteronism, and anephric man exhibit little or no response to CEI. The relationship between the renin system activity and effectiveness of CEI reflects a specific interference with a particular pathogenic mechanism which is further supported by the fact that two other types of renin system inhibitors (beta-blockers and saralasin) are similarly effective or ineffective according to the operant renin profile also by studies in patients with congestive heart failure without hypertension in whom the same relationships can be demonstrated. Like hypertensives, heart failure patients exhibit a broad spectrum of renin activity values, and their pretreatment renin levels predict the responses to CEI. We have also found that plasma renin values in heart failure are dependent on sodium intake. When salt is administered, renin falls and patients then become unresponsive to CEI.(ABSTRACT TRUNCATED AT 250 WORDS)

Renin system activity as a determinant of response to treatment in hypertension and heart failure.

In hypertension, irrespective of its underlying etiology, the baseline pretreatment renin-sodium profile predicts the antihypertensive action or the lack of it for five major types of antihypertensive drugs: 1) diuretic agents; 2) beta-receptor blockers; 3) converting-enzyme inhibitors; 4) the alpha 1 postsynaptic blocker, prazosin; and 5) the calcium channel blockers, verapamil and nifedipine. Moreover, vigorous compensatory activation of the renin-angiotensin system in response to therapy often explains initial drug ineffectiveness or resistance to treatment by diuretics and nonspecific vasodilators. This correlation between renin system behavior and antihypertensive drug efficacy likely reflect basic pharmacologic-physiologic interactions. This correlation is also observed in congestive heart failure without hypertension, where operant renin-aldosterone profiles may help to explain both drug efficacy and drug resistance to commonly administered therapeutic agents. Accordingly, a control system analysis of the renin axis has broad applications in therapy. The analysis is also conceptually significant since it exposes the operation of fundamentally different mechanisms of increased vascular resistance to flow occurring in different patients with hypertension or heart failure. One form is renin-angiotensin-mediated whereas the other, in the absence of renin, is associated with sodium-volume excess and/or abnormal alpha-adrenergic and calcium channel activity. Further definition of these two mechanisms of increased peripheral resistance could lead to a better understanding of the pathogenesis of some forms of essential hypertension and congestive heart failure.

Percutaneous transluminal renal angioplasty in renovascular hypertension due to atheroma or fibromuscular dysplasia.

We attempted percutaneous transluminal renal angioplasty in 89 patients with hypertension and renal-artery stenosis (including 51 with atheromatous and 31 with fibromuscular stenoses) who were then followed for an average of 16 months (range, 4 to 40). Angioplasty was technically successful in 87 per cent of the fibromuscular stenoses and in 57 per cent of the unilateral atheromatous stenoses but in only 10 per cent of the bilateral atheromatous stenoses. After successful angioplasty, blood pressure was reduced to normal or improved in 93 per cent of the patients with fibromuscular dysplasia and in 84 per cent of the patients with atheromatous disease. Angiographic follow-up at an average of 21.8 months in 15 patients showed persistent relief of the stenoses and a 12 per cent average increase in kidney size. Renal angioplasty is effective for long-term control of hypertension in patients with renal-artery stenosis due to fibromuscular dysplasia or unilateral non-ostial atheroma.

Carboxyhemoglobin Levels in New York City Runners.

In brief: Carboxyhemoglobin (COHb) blood levels were measured in 16 New York City runners before and after one-half hour of exercise. Subjects exercised along a highway and in a park under similar weather conditions during rush-hour traffic. These COHb levels were compared to those of ten healthy, nonsmoking volunteers who stood quietly for the same time period at one of the exercise locations. The runners' COHb rose during exercise at both locations from 1.7% to 5.1% and from 1.3% to 4.2% (p <.001). COHb levels also increased in the nonrunners but to a lesser extent (from 0.83% to 2.44%, p <.05). The data indicate that running or standing near traffic in an urban area raises COHb to the levels found in chronic cigarette smokers. These findings quantify potentially harmful exposure to carbon monoxide fumes in an urban environment.

Long-term efficacy of captopril in renovascular and essential hypertension.

Captopril was used in primary and long-term treatment of 40 treatment-resistant hypertensive patients. Of these, 21 had renovascular hypertension, seven unilateral and fourteen bilateral, and 19 had essential hypertension, 10 with high-renin and 9 with normal-renin profiles. All patients were off treatment when started on captopril therapy and were treated for at least 12 months, on the average for more than 2 years. The strategy of systematic drug withdrawal used to find the lowest effective dose of captopril led to average doses of 150 to 300 mg/day. A diuretic agent was added in 17 of the 40 patients when diastolic pressure remained greater than 105 mm Hg and a beta-adrenergic blocking agent was added for tachycardia or additional pressure control in 16 patients. Captopril alone was effective in 14 of the 40 patients. In all groups, mean supine and standing blood pressure levels were maintained at less than 140/90 mm Hg without evidence of decreased effectiveness over time. Control and treatment systolic pressures were higher in patients older than 50 years. For patients of all ages, systolic but not diastolic pressure during captopril treatment was higher in the supine position than standing. Plasma renin activity remained significantly elevated over time and aldosterone excretion usually decreased despite concurrent diuretic therapy. Captopril alone or in combination with a diuretic or beta-adrenergic blocking agent is effective in long-term treatment of drug-resistant renovascular and essential hypertension.

Comparison of antihypertensive and hormonal effects of captopril and propranolol at rest and during exercise.

Captopril and propranolol were given alone and in combination to 13 hypertensive men and the effects studied at rest (seated, supine and standing) and during exercise. The two drugs were equipotent at rest, and individual patients showed similar blood pressure responses to the two drugs. Both produced slight reduction of urinary aldosterone; when given in combination, both blood pressure and aldosterone were further reduced. During exercise the increase in blood pressure was unaffected by captopril but reduced by propranolol, and there was no correlation between individual responses to the two drugs. It is concluded that the similar effects of the two drugs on resting blood pressure are consistent with their effects on the renin-angiotensin system.

Variable response to oral angiotensin-converting-enzyme blockade in hypertensive scleroderma patients.

Twelve scleroderma patients with hypertension, seven of whom had malignant hypertension and renal failure of scleroderma renal crisis, were treated with captopril. The first dose lowered mean pressure in all patients by 21.3 mmHg; in 6 patients it relieved encephalopathy. Blood pressure was controlled in all patients. Two of 7 patients with scleroderma renal crisis had improvement in renal function; the 5 patients who did not have malignant hypertension improved or stabilized. Despite good pressure control, however, renal failure developed in 5 patients with scleroderma renal crisis. The data indicated that captopril is effective antihypertensive therapy in scleroderma and, when given early, may prevent renal failure and death.

Relationship between plasma renin and cortisol in hypertensive patients.

1. Plasma cortisol at 08.00 hours was significantly higher (P less than 0.005) in patients with high-renin essential or renovascular hypertension (22.6 +/- 1.6 microgram/100 ml) than in patients with normal-renin (15.4 +/- 1.2) or low-renin (11.9 +/- 1.2) forms of hypertension. 2. Plasma cortisol at 12.00 or 16.00 hours did not differ significantly among the three groups; thus the diurnal swing in plasma cortisol was steepest in patients with high plasma renin. 3. Among all patients studied, there was a direct relationship between 08.00 hours plasma cortisol and ambulatory plasma renin activity (r = 0.65, P less than 0.001). 4. In patients with high-renin values, 08.00 hours plasma cortisol fell by 39 +/- 6% after 10 days treatment with the converting enzyme inhibitor captopril. No consistent decreases were observed in the normal- or low-renin groups. 5. We conclude that the renin--angiotensin system may interact with the pituitary--adrenal axis to influence circulating levels of cortisol. This effect might conceivably contribute to the pathogenesis of certain high-renin states.