Clinical and hemodynamic performance of a totally flexible prosthetic ring for atrioventricular valve reconstruction

A new, totally flexible ring for atrioventricular annuloplasty is described. The technique for its insertion closely follows the principles of Carpentier's selective annulus reconstruction [4]. Ninety-nine such rings have been inserted (47 in the mitral and 52 in the triscuspid position); 45 valves were simultaneously replaced. There were 6 (4 hospital and 2 late) deaths. The thromboembolic incidence was 4.8%. No instances of dehiscence or late ring deterioration have been detected. Thirty-four patients have been recatheterized, 19 of them with mitral rings. The mitral gradients and angiographic findings show the correct functioning of the implanted ring. It is concluded that use of this flexible ring, which adapts to the continuous changes of the normal mitral annulus, produces a more physiological type of valve operation.     

Benign oesophageal stricture following oral potassium chloride therapy

A patient is described who developed a benign oesophageal stricture following cardiac surgery. A brief review of the literature is given and the possible dangers of oral potassium cholride therapy in patients with dysphagia are highlighted.     

Hemodynamic determinants of the time-course of fall in canine left ventricular pressure

The hemodynamic determinants of the time-course of fall in isovolumic left ventricular pressure were assessed in isolated canine left ventricular preparations. Pressure fall was studied in isovolumic beats or during prolonged isovolumic diastole after ejection. Pressure fall was studied in isovolumic relaxation for isovolumic and ejecting beats (r less than or equal to 0.98) and was therefore characterized by a time constant, T. Higher heart rates shortened T slightly from 52.6 +/- 4.5 ms at 110/min to 48.2 +/- 6.0 ms at 160/min (P less than 0.01, n = 8). Higher ventricular volumes under isovolumic conditions resulted in higher peak left ventricular pressure but no significant change in T. T did shorten from 67.1 +/- 5.0 ms in isovolumic beats to 45.8 +/- 2.9 ms in the ejecting beats (P less than 0.001, n = 14). In the ejecting beats, peak systolic pressure was lower, and end-systolic volume smaller. To differentiate the effects of systolic shortening during ejection from those of lower systolic pressure and smaller end-systolic volume, beats with large end-diastolic volumes were compared to beats with smaller end-diastolic volumes. The beats with smaller end-diastolic volumes exhibited less shortening but similar end-systolic volumes and peak systolic pressure. T again shortened to a greater extent in the beats with greater systolic shortening. Calcium chloride and acetylstrophanthidin resulted in no significant change in T, but norepinephrine, which accelerates active relaxation, resulted in a significant shortening of T (65.6 +/- 13.4 vs. 46.3 +/- 7.0 ms, P less than 0.02). During recovery from ischemia, T increased significantly from 59.3 +/- 9.6 to 76.8 +/- 13.1 ms when compared with the preischemic control beat (P less than 0.05). Thus, the present studies show that the time-course of isovolumic pressure fall subsequent to maximum negative dP/dt is exponential, independent of systolic stress and end-systolic fiber length, and minimally dependent on heart rate. T may be an index of the activity of the active cardiac relaxing system and appears dependent on systolic fiber shortening.     

Internal pancreatic fistulas: pancreatic ascites and pleural effusions

Thirty-four patients seen over a 10-year period with internal pancreatic fistulas are reported. In 22 patients the fistula was into the peritoneal cavity and they presented with pancreatic ascits. In 7 patients the fistula tracked up through the mediastinum into a pleural cavity, and they presented with pancreatic pleural effusions. Five patients presented with both pancreatic ascites and pancreatic pleural effusions. Diagnosis was made by finding a markedly elevated amylase and protein content in the ascitic and pleural fluids. Serum amylase was usually, but not always, elevated. Over one half of the patients had no history of inflammatory pancreatic disease. Initial treatment was non-operative using nasogastric suction, diamox, atropine, and multiple paracenteses or thoracenteses. This was successful in 48% (12/25). If non-operative therapy failed, surgery was performed to drain or resect the internal fistula. Surgery was successful in 82% (14/17). The internal pancreatic fistula was successfully demontrated in most instances by preoperative, operative, or postmortem pancreatography, or by gross observation at the time of surgery.     

Total duodenal diversion for treatment of reflux esophagitis uncontrolled by repeated antireflux procedures

The operations of Nissen, Hill, and Belsey are adequate in controlling esophaegeal reflux in the majority of patients. In a small percentage however, objective and subjective evidence of esophagitis persists in spite of repeated operations to restore lower esophageal sphincter competency. These failures are then usually treated by operative procedures of great magnitude involving organ interposition. Repeated antireflux operations directed to the gastroesophageal area may in some instances result in impairment of blood supply with an increased risk of both esophageal and gastric fistulae. In the past many observers have felt that reflux esophagitis resulted solely from the effects of acid-pepsin secretions bathing the distal esophagus. Recently experimental and clinical data have indicated the importance of duodenal contents in the etiology and perpetuation of reflux esophagitis. During a recent two year period, 6 patients with persistent reflux esophagitis uncontrolled by repeated antireflux procedures have been seen on our service. These 6 patients, underwent 12 unsuccessful antireflux operations elsewhere. Three of the 6 patients had also been subjected to vagotomy-antrectomy for a coexisting duodenal ulcer. A marked lowering of gastric acidity took place but esophageal reflux and esophagitis persisted. These three patients were treated on our service by takedown of the Billroth I anastomosis, closure of the duodenal stump and diversion of the duodenal contents into a Roux-en-Y limb. Three other patients who had undergone unsuccessful antireflux procedures alone were subjected to antral resection, Roux-en-Y diversion and transthoracid vagotomy. This simplified appraoch to the treatment of persistent esophageal reflux uncontrolled by repeated antireflux procedures has given satisfactory results. The operation should be considered when technical considerations preclude further surgical attempts to perform another effective antireflux operation. Total duodenal diversion should, however, not be considered as the primary operation for the patient suffering from reflux esophagitis. However, in circumstances discussed above this direct approach appears preferable to major resectional procedures.     

The role of insulin and glucagon in the regulation of basal glucose production in the postabsorptive dog

The aim of the present experiments was to determine the role of insulin and glucagon in the regulation of basal glucose production in dogs fasted overnight. A deficiency of either or both pancreatic hormones was achieved by infusin somatostatin (1 mug/kg per min), a potent inhibitor of both insulin and glucagon secretion, alone or in combination with intraportal replacement infusions of either pancreatic hormone. Infusion of somatostatin alone caused the arterial levels of insulin and glucagon to drop rapidly by 72+/-6 and 81+/-8%, respectively. Intraportal infusion of insulin and glucagon at rates of 400 muU/kg per min and 1 ng/kg per min, respectively, resulted in the maintenance of the basal levels of each hormone. Glucose production was measured using tracer (primed constant infusion of [3-3H]glucose) and arteriovenous difference techniques. Isolated glucagon deficiency resulted in a 35+/-5% (P less than 0.05) rapid and sustained decrease in glucose production which was abolished upon restoration of the plasma glucagon level. Isolated insulin deficiency resulted in a 52+/-16% (P less than 0.01) increase in the rate of glucose production which was abolished when the insulin level was restored. Somatostatin had no effect on glucose production when the changes in the pancreatic hormone levels which it normally induces were prevented by simultaneous intraportal infusion of both insulin and glucagon. In conclusion, in the anesthetized dog fasted overnight; (a) basal glucagon is responsible for at least one-third of basal glucose production, (b) basal insulin prevents the increased glucose production which would result from the unrestrained action of glucagon, and (c) somatostatin has no acute effects on glucose turnover other than those it induces through perturbation of pancreatic hormone secretion. This study indicates that the opposing actions of the two pancreatic hormones are important in the regulation of basal glucose production in the postabsorptive state.