Graeme L. Hammond

What is the appropriate size criterion for resection of thoracic aortic aneurysms

Although many articles have described techniques for resection of thoracic aortic aneurysms, limited information on the natural history of this disorder is available to aid in defining criteria for surgical intervention. Data on 230 patients with thoracic aortic aneurysms treated at Yale University School of Medicine from 1985 to 1996 were analyzed. This computerized database included 714 imaging studies (magnetic resonance imaging, computed tomography, echocardiography). Mean size of the thoracic aorta in these patients at initial presentation was 5.2 cm (range 3.5 to 10 cm). The mean growth rate was 0.12 cm/yr. Overall survivals at 1 and 5 years were 85% and 64%, respectively. Patients having aortic dissection had lower survival (83% 1 year; 46% 5 year) than the cohort without dissection (89% 1 year; 71% 5 year). One hundred thirty-six patients underwent surgery for their thoracic aortic aneurysms. For elective operations, the mortality was 9.0%; for emergency operations, 21.7%. Median size at time of rupture or dissection was 6.0 cm for ascending aneurysms and 7.2 cm for descending aneurysms. The incidence of dissection or rupture increased with aneurysm size. Multivariable regression analysis to isolate risk factors for acute dissection or rupture revealed that size larger than 6.0 cm increased the probability by 32.1 percentage points for ascending aneurysms (p = 0.005). For descending aneurysms, this probability increased by 43.0 percentage points at a size greater than 7.0 cm (p = 0.006). If the median size at the time of dissection or rupture were used as the intervention criterion, half of the patients would suffer a devastating complication before the operation. Accordingly, a criterion lower than the median is appropriate. We recommend 5.5 cm as an acceptable size for elective resection of ascending aortic aneurysms, because resection can be performed with relatively low mortality. For aneurysms of the descending aorta, in which perioperative complications are greater and the median size at the time of complications is larger, we recommend intervention at 6.5 cm.

Penetrating ulcer of the thoracic aorta: What is it? How do we recognize it? How do we manage it?

BACKGROUND Although classic type A and B aortic dissections have been well described, less is known about the natural history of penetrating atherosclerotic ulcers of the thoracic aorta. This study differentiates penetrating ulcer from aortic dissection, determines the clinical features and natural history of these ulcers, and establishes appropriate correlates regarding optimal treatment. METHODS A retrospective review of patient records and imaging studies was conducted with 198 patients with initial diagnoses of aortic dissection (86 type A, 112 type B) at our institution from 1985 to 1997. RESULTS Of the 198 patients, 15 (7.6%) were found to have a penetrating aortic ulcer on re-review of computed tomographic scans, magnetic resonance images, angiograms, echocardiograms, intraoperative findings, or pathology reports. Two ulcers (13.3%) were located in the ascending aorta; the other 13 (86.7%) were in the descending aorta. In comparison with those with type A or B aortic dissection, patients with penetrating ulcer were older (mean age 76.6 years, p = 0.018); had larger aortic diameters (mean diameter 6.5 cm); had ulcers primarily in the descending aorta (13 of 15 patients, 86.7%); and more often had ulcers associated with a prior diagnosed or managed AAA (6 of 15 patients, 40.0%; p = 0.0001). Risk for aortic rupture was higher among patients with penetrating ulcers (40.0%) than patients with type A (7.0%) or type B (3.6%) aortic dissection (p = 0.0001). CONCLUSIONS Accurate recognition and differentiation of penetrating ulcers from classic aortic dissection at initial presentation is critical for optimal treatment of these patients. For penetrating ulcer, the prognosis may be more serious than with classic type A or B aortic dissection. Surgical management is advocated for penetrating ulcers in the ascending aorta and for penetrating ulcers in the descending aorta that exhibit early clinical or radiologic signs of deterioration.

Long-term experience with descending aortic dissection: The complication-specific approach

We analyzed long-term results in 71 patients (45 men and 26 women) treated over 17 years for documented descending aortic dissection. Forty-nine patients were treated medically and 22, surgically. Actuarial survival was 65% at 1 year, 57% at 3 years, 50% at 5 years, and 28% at 10 years for the whole group. For the group treated medically, survival was 73%, 63%, 58%, and 25% at 1 year, 3 years, 5 years, and 10 years, respectively, and for the group treated surgically, 47%, 40%, and 28% at 1 year, 3 years, and 5 years, respectively. Ten (20.4%) of the 49 medically treated patients died early (5 of rupture), and 14 (28.6%) died late (8 of dissection). Five medically treated patients crossed over to surgical management for complications of dissection. Among the surgically treated patients, 6 underwent standard graft replacement of the proximal descending aorta, 8 underwent the fenestration procedure (with a standardized retroperitoneal abdominal approach), and 4 underwent the thromboexclusion operation. Specific analysis of fenestration in 14 patients (including some with persistent descending aortic dissection after replacement of the ascending aorta for dissection) found it to be safe and effective. Actuarial survival after fenestration was 77%, 77%, and 53% at 1 year, 3 years, and 5 years, respectively. Thromboexclusion was found effective, and postoperative studies confirmed thrombosis of the descending aorta with preservation of the lowest intercostal arteries. Fifteen of the 21 surviving medically treated patients agreed to return for follow-up imaging. Nine had thrombosis of the false lumen. An interesting radiographic finding was that 4 of the 15 restudied patients had a saccular aneurysm in the aorta at the level of the left subclavian artery. We recommend a complication-specific approach to the management of descending aortic dissection. Uncomplicated dissection is treated medically, whereas complicated dissection is treated surgically, with realized rupture treated by standard graft replacement, limb ischemia treated by fenestration, and enlargement or impending rupture treated by thromboexclusion.

Surgical intervention criteria for thoracic aortic aneurysms : A study of growth rates and complications

BACKGROUND Evidence regarding the behavior of thoracic aortic aneurysm (TAA) is limited. This study reviews our ongoing efforts to understand the factors influencing aortic growth rates and the complications of rupture and dissection in order to define scientifically sound criteria for surgical intervention. METHODS Data from 370 patients with TAA treated at Yale University School of Medicine from January 1985 to June 1997 were analyzed. This computerized data base included 1063 imaging studies (magnetic resonance imaging, computed tomography, and echocardiography). RESULTS The mean size of the thoracic aorta in these patients at initial presentation was 5.2 cm (range 3.5-10). The mean growth rate was 0.10 cm/year. Median size at the time of rupture or dissection was 5.9 cm for ascending and 7.2 cm for descending aneurysms. The incidence of dissection or rupture increased with aneurysm size. Multivariable regression analysis to isolate risk factors for acute dissection or rupture revealed that size > or = 6.0 cm increased the probability of these devastating complications by 25.2% for ascending aneurysms (p = 0.006 compared with aneurysms 4.0-4.9 cm). For descending aneurysms > or = 7.0 cm, risk of dissection or rupture was increased by 37.3% (p = 0.031). CONCLUSIONS If the median size at time of dissection or rupture had been used as the indication for intervention, half the patients would have suffered a devastating complication before surgery. Accordingly, a criterion lower than the median is appropriate. We recommend 5.5 cm as an acceptable size for elective resection of ascending aortic aneurysms because this operation can be performed with relatively low mortality. For aneurysms of the descending aorta, where perioperative complications are greater and the median size at the time of complication is larger, we recommend intervention at 6.5 cm.

Results and Complications of Intraaortic Balloon Counterpulsation

During the forty-month period ending July, 1976, intraaortic balloon counterpulsation was used as an adjunct to medical or surgical therapy in 273 patients. Thirty-seven developed complications. Limb ischemia occurred in 16; it resolved in 12, resulted in gangrene of the toes in 1 and leg gangrene in 2, and was the casue of death in 1 patient. Aortic dissection was confirmed in 7 patients and strongly suspected in another 4. Eight of the 11 patients with dissection underwent cardiac procedures with heparinization at two days to three months after balloon insertion with no untoward effects. Septicemia developed in 2 patients, 1 of whom died of cardiogenic shock. Localized groin sepsis occurred in 8 patients, 2 of whom required removal of infected Dacron graft material. Awareness of the complications of balloon insertion, proper attention to details of balloon management at the time of insertion and removal, and continuous monitoring through a central-lumen balloon should decrease the incidence of complications.

Optimal Timing of Coronary Artery Bypass Graft Surgery After Acute Myocardial Infarction

BACKGROUND To assess optimal timing for coronary artery bypass graft surgery (CABG) after an acute myocardial infarction (AMI), all patients undergoing CABG without associated procedures at our institution from January 1, 1991, to July 30, 1992, were reviewed. Patients were divided into three groups based on time from infarct to revascularization. The control group consisted of patients operated on for angina refractory to medical management. Relative risks (incident infarction group divided by incident control group) were established for need of vasopressors, new balloon to separate from bypass, perioperative myocardial infarction, and hospital mortality. METHODS AND RESULTS One hundred sixteen patients underwent CABG within 6 weeks of infarction. In the experimental group, 58 patients underwent CABG for non-Q-wave infarction, and 58 patients underwent CABG for Q-wave infarction. In the control group, 255 patients underwent surgery for angina without infarction. Patients were analyzed by group relative to the time between infarction and CABG. Patients were analyzed between infarction and CABG and assigned to one of three groups. Group 1 patients were revascularized within 48 hours; group 2, between 3 and 5 days; and group 3, after 5 days. Significance was determined by Fishers exact or Mantel-Haenszel chi 2 test where appropriate. Multivariate analysis was performed on statistics that were significant. All patients within all groups after Q-wave or non-Q-wave myocardial infarction had a significantly higher risk of needing an intra-aortic balloon pump and vasopressors to be weaned from bypass and a greater incidence of perioperative MI compared with control patients. Surgical mortality is highest immediately after Q-wave infarctions. CONCLUSIONS Patients with non-Q-wave infarction may undergo CABG relatively safely at any time. Acceptable timing for CABG after Q-wave infarction is after 48 hours.

Late cardiac tamponade after open heart surgery: incidence, role of anticoagulants in its pathogenesis and its relationship to the postpericardiotomy syndrome.

Cardiac tamponade that occurs late after cardiac surgery (7 days) is relatively uncommon but potentially fatal. We analyzed its incidence, clinical course and relationship to the postpericardiotomy syndrome in 1290 consecutive adult patients who survived surgery. Criteria for diagnosis of cardiac tamponade were (1) elevated jugular venous pressure, (2) hypotension or decreased cardiac index, (3) characteristic hemodynamics at cardiac catheterization, and (4) echocardiographic evidence of pericardial effusion.Ten of the 1290 patients (0.8%) developed cardiac tamponade. Surgery was for congenital heart disease in five patients, valvular heart disease in two patients, and coronary artery disease in three patients. The onset of hemodynamic compromise ranged from 15–180 days postoperatively (mean 49 days). All patients had echocardiographic evidence of pericardial fluid, eight had a pericardial friction rub at the time of cardiac tamponade, nine had pericardial pain, and all were considered to have a postpericardiotomy syndrome. One patient was receiving coumadin and two patients were receiving aspirin before the diagnosis of cardiac tamponade. Nine patients underwent pericardiocentesis (0.5–1 1 of fluid). There were no deaths in the group. The syndrome resolved in nine patients with conservative medical therapy and one patient required pericardial stripping for recurrent cardiac tamponade.In this study, cardiac tamponade occurred in 0.8% of patients who survived cardiac surgery; cardiac tamponade occurred in patients without prior anticoagulation, in marked contrast to previously reported cases; pericardiocentesis and conservative medical therapy were successful in treating the majority of patients; clear symptoms and signs of pericardial involvement were present before cardiac tamponade occurred.

Noncardiogenic pulmonary edema after cardiopulmonary bypass. An anaphylactic reaction to fresh frozen plasma.

Nine episodes of fulminant noncardiogenic pulmonary edema after cardiopulmonary bypass were observed in eight patients between September 1977 and December 1982. All these catastrophic reactions occurred during administration of fresh frozen plasma 30 minutes to 6 hours after discontinuation of cardiopulmonary bypass. In one patient, two episodes of noncardiogenic pulmonary edema occurred 4 hours apart. In each instance, fresh frozen plasma was being administered. In all patients, pulmonary artery diastolic pressure became elevated during the administration of fresh frozen plasma while left atrial pressure or pulmonary capillary wedge pressure progressively decreased, and cardiac output deteriorated markedly in all but one patient. Corticosteroids, positive end-expiratory pressure, and catecholamines were administered to all patients. All deaths were due to a decrease in cardiac output. Cardiac output did not increase substantially with the use of an intraaortic balloon pump or the administration of catecholamines. The last two patients in the series showed a steady and remarkable improvement in cardiac output when the wedge pressure was increased to a level above 15 mm Hg with the administration of normal saline solution. Our data suggest the following: (1) noncardiogenic pulmonary edema after cardiopulmonary bypass is most probably an anaphylactic reaction to fresh frozen plasma. (2) The syndrome is reversible within hours; in only one patient (who suffered noncardiogenic pulmonary edema twice) did adult respiratory distress syndrome develop. (3) The three deaths were not related to hypoxia but to the deleterious effects of low cardiac output associated with hypovolemia secondary to fluid loss through the lungs and possibly across other capillary beds. Therefore, treatment should include restoration of adequate left-sided filling pressures to achieve satisfactory cardiac output.

Continuous monitoring of left ventricular performance with the computerized nuclear probe during laryngoscopy and intubation before coronary artery bypass surgery

Abstract Left ventricular performance was monitored serially in 25 patients during laryngoscopy and intubation in the anesthetic induction period before elective coronary artery bypass surgery using the labeled equilibrium blood pool and the computerized nuclear probe. Left ventricular ejection fraction was obtained preoperatively, after induction of anesthesia but before endotracheal intubation, immediately after intubation, and at 1 minute intervals thereafter for 10 minutes. In all patients, there was an immediate decrease (mean 16%) in left ventricular ejection fraction accompanying the reflex hypertension and tachycardia occurring during laryngoscopy and endotracheal intubation; it was significantly depressed for 3 minutes with the concomitant hemodynamic changes. Seven patients did not demonstrate a recovery of left ventricular ejection fraction to the preintubation value. In 10 healthy noncardiac patients undergoing orthopedic surgery, after an identical anesthetic induction sequence and intubation, there was a similar decrease in ejection fraction, but of shorter duration. In these patients the recovery of left ventricular performance preceded the recovery of blood pressure and heart rate. This study demonstrates that profound decreases in left ventricular performance accompany the reflex hypertension and tachycardia occurring during endotracheal intubation and that there is persisting depression of left ventricular function in some patients with coronary artery disease. These findings indicate the potential utility of the computerized nuclear probe for monitoring ventricular performance during this critical period.

Alcohol-induced prinzmetal variant angina

Prinzmetal variant angina occurred in a 47 year old man only in association with the ingestion of alcohol. Results of exercise testing were normal. Coronary arteriography substantiated the presence of two significant coronary lesions. Double aortocoronary saphenous vein bypass grafts resulted in complete relief of symptoms.