Otto Nordhus

Renal artery reconstruction in renovascular hypertension.

Over a period of 8 years, 52 patients (31 females and 21 males) between 12 and 59 years of age (mean age 40 years) underwent renal artery reconstruction for correction of renovascular hypertension. Five patients were operated on bilaterally. A thoracoretroperitoneal approach was chosen at 48 of 57 renal artery reconstructions. The most used types of arterial reconstruction were thrombendarterectomy and vein patch, resection of the stenosis and end-to-end anastomosis, vein patch only or aortorenal vein bypass. No early or late nephrectomies were performed. These was no operative mortality, but 3 late deaths occurred. Twenty-two patients were normotensive postoperatively, 20 were improved and there were 10 failures. The follow-up time as 1--8 years. The blood pressures were measured after withdrawal of antihypertensive drugs for at least 10 days. The best predictable criterion for normotension was a positive renin test with a renin ratio of 1.5 or more. The normotensive patients were in the younger age group with a shorter duration of known hypertension and had mainly fibromuscular hyperplasia.

Persisting hypertension after renal artery reconstruction. A follow-up study.

Twenty-four patients with persisting hypertension after renal artery reconstruction were re-investigated 1--8 years after surgery. They underwent renal arteriography, determination of plasma renin activity, renography and renal function studies in order to find the causes of the postoperative hypertension. Restenosis was found in 6 patients, in 3 of whom it was of functional significance according to the positive renin tests (renin ratio greater than 1.5). Positive renin tests were found in 2 other patients. One had occlusion of a renal artery branch and the other hypoplasia of the kidney due to chronic nephritis. No explanation of the persisting hypertension could be found in 19 patients at re-examination. In 10 of them, however, biopsy from the affected kidney obtained during operation showed nephrosclerosis, which may explain the outcome. Fourteen of the 19 patients had negative renin tests preoperatively. These negative tests indicate that renal artery stenosis was not the only cause of hypertension. It may be concluded that the renin test is of the utmost value in the selection of patients for renal artery reconstruction and should always be considered. A biopsy from the contralateral kidney may be necessary in order to detect other causes of hypertension than renal artery stenosis. The importance of re-investigating patients with persisting hypertension is confirmed by the present study.

Surgical management of obliterative disease of the brachiocephalic trunk. Experience from 24 cases.

Transsternal endarterectomy was performed in 24 patients for symptomatic obliterative disease of the brachiocephalic trunk in the period 1961-1981. In 10 of the patients the vessel was occluded, and in 14 there were various degrees of stenosis. Reversal of vertebral artery flow was found in 15 patients. Subclavian steal-carotid recovery phenomenon was present in six patients, and one patient had reversed flow in both the right vertebral and the common carotid artery. Only 10 of the 24 patients were free from obliterative changes in other extracranial arteries. After the reconstruction, the blood flow in the brachiocephalic trunk increased from 370 to 610 ml/min in patients with stenosis, and from 0 to 692 ml/min in patients with occlusion. The flow rate changed in the right vertebral artery from -58 to + 119 ml/min and in the right common carotid artery from 116 to 340 ml/min. Two patients died in the early postoperative period (8.5%) and six died during the follow-up period. Follow-up was possible in 21 patients. The result of endarterectomy was assessed as cure in 14, improvement in two and failure in three patients. Stroke occurred in two patients.

Negative Effects of Dihydroergotamine (Orstanorm®) on Central Haemodynamics and Aorto-Coronary Bypass Blood Flow: An Intraoperative Study

Dihydroergotamine (DHE), Orstanorm, because of its strong constrictor action on capacitance vessels, is used in the treatment of hypotension caused by orthostatism or spinal or epidural anaesthesia. Lately Orstanorm has also been used in combination with heparin as prophylaxis against postoperative thromboembolism. In the present study, Orstanorm (0.01 mg/kg b.w.) was given intravenously to 20 patients after coronary bypass surgery. Coronary bypass blood flow, heart rate, systemic mean and systolic blood pressures, right and left atrial pressures, pulmonary artery pressure and cardiac output were measured. Stroke volume, cardiac index, stroke index, systemic and regional myocardial vascular resistance and cardiac work index were then calculated. The results showed that despite increased filling pressures there was no rise in cardiac output, and despite increased cardiac work the bypass flow significantly decreased. The significant increase in regional myocardial vascular resistance found after administration of DHE may explain the absence of expected increase of cardiac output and coronary bypass flow.

Central, High Flow Subclavian Artery-Internal Jugular Vein Fistula for Venous Access

A subclavian artery--internal jugular vein shunt was created for intermittent parenteral infusions in six patients who had undergone extensive intestinal resection because of Crohns disease or ulcerative colitis. The flow rates through the shunt were initially around 1000 ml/min. In three patients the flow later increased, giving rise to mild cardiac symptoms. Slight disturbance from arm ischemia during work was experienced by two patients. Some patients were disturbed by murmurs from the shunt when the flow increased. Narrowing of the vein at the end-to-side anastomosis diminished excessive flow and relieved symptoms. There was no perioperative mortality, and no septic, hemorrhagic or wound healing complications occurred in connection with the six primary and nine secondary operations. The patency rate of fistula was 100% after one year, 83% after two years and 66% after three years. The shunt was well accepted by patients and by personnel. This type of A-V fistula for intermittent parenteral infusions seems to be a feasible alternative to other A-V shunts when the usual vascular access routes have been exhausted.

Effects of pentoxifylline on central hemodynamics in patients with congestive heart failure

Pentoxifylline, a xanthine derivative with vasoactive and hemorheologic properties, was studied in regard to effect on central hemodynamics in ten patients with congestive heart failure due to aortic or mitral valve disease, mainly in NYHA group III or IV. The drug was infused intravenously in a dose of 4 mg/kg b.w. during a stable hemodynamic situation after valve replacement. The heart rate, systemic blood pressure, central venous and pulmonary artery pressures and cardiac output were recorded, and the stroke volume, cardiac index and systemic vascular resistance were calculated. Significant increase in cardiac output from the baseline value of 4.92 l/min was found 5-10 min (+22.6%) and 25-30 min (+19.5%) after pentoxifylline infusion. Cardiac index similarly increased from baseline, 2.73 dsc-5 (+22.3 and +18.3, respectively). The systemic vascular resistance showed significant decrease at the same intervals (-20.6 and -15.5%). The heart rate and stroke volume were significantly increased after 5-10 min. The systemic mean blood pressure and the pulmonary artery and central venous pressures showed no significant changes. There were no adverse effects of pentoxifylline.

HAEMODYNAMIC STUDIES IN RENAL ARTERY STENOSIS

With the aid of an electromagnetic flowmeter and a mechano-electrical pressure transducer, peroperative renal artery blood flows and pressures in the aorta and the renal artery distal to the stenosis were measured in 48 patients with renovascular hypertension before and after renal artery reconstruction. Calculations of pressure difference across the stenosis and resistances over the stenosis and the renal parenchyma were made. There was a significant blood flow increase through the renal artery after arterial reconstruction in all patients, irrespective as to whether they were normotensive, improved or failures postoperatively. The pressure difference across the stenosis after reconstruction was eliminated in all 3 groups of patients. The highest resistances over both the stenosis and the renal parenchyma before arterial reconstruction were found in the normotensive group, but there was no significant variation between the 3 groups. After reconstruction, a significant decrease in resistance over the renal parenchyma was found in the normotensive and the improved group of patients. The resistance of the stenosis was higher than over the renal parenchyma only in the postoperatively normotensive patients. This indicates that the removal of a resistance over the renal artery stenosis, that is higher than that over the renal parenchyma, gives the most favourable long-term results concerning normalization of the blood pressure.