Melvin R. Platt

Intraaortic balloon counterpulsation in patients in cardiogenic shock, medically refractory left ventricular failure and/or recurrent ventricular tachycardia

Of the 27 patients described, 23 were in cardiogenic shock, 2 had severe left ventricular failure, and 2 had medically refractory ventricular tachycardia. Utilizing intraaortic counterpulsation, adequate systemic blood pressure was initially restored in 19 patients. Nine of these were subsequently weaned from circulatory assistance, but only three were discharged from the hospital and are currently alive. The remaining 10 patients who derived initial benefit from circulatory assistance were balloon-dependent in that they could not be weaned from circulatory assistance. Eight of these patients subsequently underwent cardiac catheterization; four had inoperable disease. The remaining four patients underwent surgery for either resection of the area of infarction and/or for myocardial revascularization; only one survived to subsequently leave the hospital. Ventricular volumes were abnormal and ejection fractions were below 30 per cent in all the patients in cardiogenic shock except one who underwent cardiac catheterization and ultimately died. Ejection fractions were greater than 30 per cent in the two patients with cardiogenic shock who were weaned from balloon support and survived to leave the hospital without surgery. Both of these patients had inferior myocardial infarction. The data obtained from this experience suggest that intraaortic counterpulsation is a very useful adjunct to currently existing medical measures to treat both cardiogenic shock and medically refractory left ventricular failure but that most patients have such extensive disease that they can neither be weaned from balloon support nor undergo successful infarctectomy or myocardial revascularization.

Influence of dobutamine on regional myocardial blood flow and ventricular performance during acute and chronic myocardial ischemia in dogs.

The data from this study document that dobutamine is a powerful inotropic agent in anesthetized dogs with acute myo-cardial ischemia and in awake, unsedated ones with chronic myo-cardial infarction. Dobutamine significantly increases heart rate at relatively small doses in anesthetized dogs with acute myocardial ischemia but considerably larger amounts of dobutamine are required to significantly increase heart rate in awake, unsedated dogs with myocardial infarction. Dobutamine also significantly increases regional myocardial blood flow to all areas of the heart at 20μg/kg/min in both anesthetized dogs with acute myocardial ischemia and awake, unsedated ones with myocardial infarction. However, in anesthetized dogs 20μg/kg/min of dobutamine significantly increases epicardial ST-segment elevation during acute myocardial ischemia. Propranolol prevents the inotropic and chronotropic effects of dobutamine in both anesthetized and awake, unsedated dogs. This study suggests that during experimental acute myocardial ischemia dobutamine given at doses that significantly in-crease heart rate and contractility may increase the extent of myocardial damage. The data also suggest that this agent should be of value in the setting of severe myocardial depression without as-sociated severe coronary artery disease to increase cardiac contractil-ity at doses that do not markedly alter heart rate. The hemodynamic and coronary blood flow effects of dobutamine in patients with and without severe coronary artery disease should be evaluated.

Influence of aging on left ventricular hemodynamics and stiffness in beagles.

We studied the influence of aging on the contractile performance, stiffness, and contraction time of the canine left ventricle. Eight young (27 ± 2.5 months, mean ± SE) and seven old (128 ± 20.5 months) beagles were placed on complete cardiopulmonary bypass, the arterial pressure was adjusted to 80 mm Hg, and the heart contracted isovolumically at a paced rate of 120 beats/min. Diastolic pressure-volume curves were established for each unpaced left ventricle at the beginning of each experiment, and the volume at the knee of the curve was used during the subsequent data collection when the heart was paced. Stiffness was measured with a sinusoidal forcing function, which imposed a sinusoidal volume displacement of 1 ml at 20 Hz into a balloon placed in the left ventricle. In each ventricle, stiffness was related linearly to pressure during the cardiac cycle, and was greater for any given pressure in the older beagles. Contraction duration was prolonged in the older dogs. In an additional seven old beagles during right heart bypass, time and duration of contraction were longer than in seven young beagles. Aging of the beagle heart is associated with an increase in left ventricular systolic and diastolic stiffness and prolonged duration of contraction. Circ Res 44: 189-194, 1979

Unstable angina pectoris: a randomized study of patients treated medically and surgically.

Fifty patients with the clinical syndrome of unstable angina pectoris were evaluated. Twenty-seven were randomized into medical or surgical treatment groups and subsequently followed up. The results of the study reveal that: (1) there is approximately a 16 percent incidence rate of significant left main coronary artery disease in patients with this entity at our institution; (2) 10 percent of patients do not have angiographically significant coronary artery disease; (3) pain relief is better in the surgically treated patients, but the 1 1/2 year survival rate is not significantly different between the groups; (4) 50 percent of the medically treated patients again had the syndrome of unstable angina pectoris in the initial few months of the follow-up period; (5) the operative and late postoperative mortality rate in patients presenting with unstable angina pectoris and left main coronary artery disease in this small group of patients was 43 percent; and (6) four of six patients with this syndrome whose condition was deemed inoperable and who were not randomized died within the subsequent few months.

Avoidance of Esophageal Stricture Following Severe Caustic Burns by the Use of an Intraluminal Stent

The high incidence of stricture following conventional therapy for caustic esophageal injuries prompted us to incorporate the esophageal stenting technique of Reyes and colleagues [3, 5, 6] into our protocol for management of such patients. Four adult patients were treated following severe esophageal burns caused by the ingestion of caustic drain cleaner. The severity of the burn was established by early esophagoscopy. Laparotomy and gastrotomy revealed severe but nontransmural gastric burns. The stent was left in place for 21 days. Antibiotics and corticosteroids were also employed. There have been no late strictures. One patient required laryngeal dilation for adhesions and another, tracheal dilation for subglottic stenosis. Contrast roentgenographic studies and esophageal manometry have revealed nearly normal esophageal function up to 20 months following the injury.

Technetium stannous pyrophosphate myocardial scintigrams in the recognition of myocardial infarction in patients undergoing coronary artery revascularization.

Myocardial imaging using technetium 99m stannous pyrophosphate (99mTc-PYP) has been utilized preoperatively and three to five days postoperatively to detect myocardial infarction in 48 patients undergoing aortocoronary bypass grafting, including 7 having valve replacement (5 aortic, 2 mitral) in addition to revascularization. In the total group of patients operated on there were 3 deaths (6%). Preoperatively, 26 patients had unstable angina and 10 had severe left main coronary artery disease. Eleven of the 48 (23%) were women. ECG and enzyme-proved infarctions occurred in 6 of the 48 patients (12%), but the addition of 99mTc-PYP myocardial imaging demonstrated scintigraphic evidence of infarction in 15 patients (31%), including 2 who died in the operating room. The 99mTc-PYP myocardial imaging technique, which has proved safe, simple, and relatively inexpensive in these patients, suggests that the incidence of infarction after coronary bypass operations is somewhat higher than has been previously recognized from just ECG and enzyme changes. This technique also has been of value in helping to exclude myocardial infarction in difficult clinical situations such as postoperative arrhythmias and the postpericardiotomy syndrome.

Systemic arterial air embolism in penetrating lung injury

Systemic arterial air embolism is frequently unrecognized as a cause of death among patients with isolated penetrating lung injury. Between 1975 and 1983 at Parkland Memorial Hospital, the complication of systemic arterial air embolism developed in 9 patients with penetrating lung injury (six gunshots and three stabbings). Eight patients were either in profound shock or experienced cardiac arrest and all were intubated and on positive-pressure ventilation, frequently on a manual resuscitator bag before or at the time of diagnosis. The diagnosis was made by direct visualization of air in the coronary vessels in all 9 patients, and in 3 air was also aspirated from the left ventricular apex and aortic root. In addition, 5 patients had clinically significant hemoptysis. At operation, only an isolated injury to the lung was found in 7 of the 9 patients. Arterial air embolism is a highly lethal complication; 6 of our patients died, a mortality rate of 66%. Thus, it clearly behooves us to be more alert to the possible occurrence of this complication among all victims of penetrating chest trauma. We must accept that systemic arterial air embolism is an established complication of penetrating lung injury and must recognize that it occurs much more frequently than has been previously reported. Prompt diagnosis coupled with aggressive efforts at cardiopulmonary resuscitation is crucial for successful management of patients with air embolism.

Marked thrombosis and calcification of porcine heterograft valves.

Prosthetic valvular dysfunction resulting in clinically significant complications occurred in six patients with Hancock porcine heterografts. In one patient with a prosthetic valve in the aortic position, massive prosthetic thrombosis resulted in sudden death. In two patients who had a mitral prosthesis, thrombosis resulted in congestive heart failure and systemic embolization; in one of the latter patients, the thrombi were infected with Candida sp. Calcification of organizing thrombi and cusp tissue resulted in valvular stenosis and congestive heart failure in one patient with an aortic prosthesis and in two patients with mitral prostheses. Four of the six patients died. The prosthetic valves had been in place for 6 months to 3 years before onset of complications. During the same 4-year interval, over 400 porcine prostheses were inserted. This report provides further clarification of the nature and frequency of clinical complications related to degeneration and thrombosis of Hancock porcine heterograft valves.

Massive Pulmonary Embolism: A Complication of the Technique of Tourniquet Ischemia

Various neurologic and vascular injuries complicating the technique of tourniquet ischemia for limb surgery are well known. We found no reports of the serious complication of massive pulmonary embolism as a consequence of this technique. This is surprising when one considers the type of patients surgeons deal with in the use of the technique of tourniquet ischemia. These patients are traumatized and immobile, with high potential for development of deep venous thromboembolic disease, and are subjected to extensive extremity manipulation. Such patients are ideal candidates for the development of massive pulmonary embolism. We have encountered and successfully treated a patient with such a complication.

Rupture of the right hemidiaphragm with liver herniation: Report of a case with extension of a tear of a previously undiagnosed ruptured right hemidiaphragm

Right-sided blunt diaphragmatic rupture is not uncommon. Its incidence has definitely increased. As expected, total or partial herniation of the liver commonly occurs with this entity. Diaphragmatic-pericardial rupture with visceral herniation into the pericardial cavity and other rare injuries have been diagnosed, but we found no report of extension of a diaphragmatic tear of a previously undiagnosed right-sided diaphragmatic rupture with total herniation of the liver. Such a case is reported here.