Myocardial infarction after vascular surgery: the role of prolonged stress-induced, ST depression-type ischemia.

OBJECTIVES: The goal of this study was to investigate the nature of the association between silent ischemia and postoperative myocardial infarction (PMI). BACKGROUND: Silent ischemia predicts cardiac morbidity and mortality in both ambulatory and postoperative patients. Whether silent stress-induced ischemia is merely a marker of extensive coronary artery disease or has a closer association with infarction has not been determined. METHODS: In 185 consecutive patients undergoing vascular surgery, we correlated ischemia duration, as detected on a continuous 12-lead ST-trend monitoring during the period 48 h to 72 h after surgery, with cardiac troponin-I (cTn-I) measured in the first three postoperative days and with postoperative cardiac outcome. Postoperative myocardial infarction was defined as cTn-I >3.1 ng/ml accompanied by either typical symptoms or new ischemic electrocardiogram (ECG) findings. RESULTS: During 11,132 patient-hours of monitoring, 38 patients (20.5%) had 66 transient ischemic events, all but one denoted by ST-segment depression. Twelve patients (6.5%) sustained PMI; one of those patients died. All infarctions were non-Q-wave and were detected by a rise in cTn-I during or immediately after prolonged, ST depression-type ischemia. The average duration ofischemia in patients with PMI was 226+/-164 min (range: 29 to 625), compared with 38+/-26 min (p = 0.0000) in 26 patients with ischemia but not infarction. Peak cTn-I strongly correlated with the longest, as well as cumulative, ischemia duration (r = 0.83 and r = 0.78, respectively). Ischemic ECG changes were completely reversible in all but one patient who had persistent new T wave inversion. All ischemic events culminating in PMI were preceded by an increase in heart rate (delta heart rate = 32+/-15 beats/min), and most (67%) of them began at the end of surgery and emergence from anesthesia. CONCLUSIONS: Prolonged, ST depression-type ischemia progresses to MI and is strongly associated with the majority of cardiac complications after vascular surgery.

Transient neurological events during dipyridamole stress test: an arterial steal phenomenon?

Dipyridamole-associated adverse neurological side effects have not been extensively described. We present two cases of dipyridamole-associated transient motor neurological events with no evidence of residual neurological deficits detected clinically or by head CT. The patients showed no evidence of significant extracranial (internal carotid) artery disease. We propose the presence of a regional cerebral perfusion disturbance due to an intracranial vascular steal phenomenon as the mechanism for the above side effects of dipyridamole.

Systemic embolization following thrombolytic therapy for acute myocardial infarction.

We describe a patient with acute inferior myocardial infarction who developed a "saddle" aortic embolus during streptokinase infusion. Three months previously, this patient had sustained an anterior infarction, and an apical aneurysm was found. This patient's embolus had most probably originated from a left ventricular mural thrombus that had been dislodged by streptokinase. As fibrinolytic treatment is gaining wide acceptance, physicians should be aware of this rare, but possible, complication.

Insulin-like growth factor-I (IGF-I) and IGF-I receptor gene expression in the kidney of the chronically hypoinsulinemic rat and hyperinsulinemic rat.

Acute streptozotocin (STZ)-induced diabetes in rats causes a transient increase in insulin-like growth factor-I (IGF-I) in the kidney, followed by a rapid renal hypertrophy and constant renal hyperperfusion. However, renal IGF-I levels return to normal within 4 days. Thus, hyperperfusion, which is independent of renal hypertrophy of the chronically diabetic kidney, is not explained by increased renal IGF-I. We studied IGF-I and IGF-I receptor gene expression in the kidney of rats with long-standing STZ-induced diabetes. IGF-I mRNA level in the chronically diabetic kidney was approximately 50% of that in control rats, whereas IGF-I receptor mRNA was increased approximately threefold. Ten days' treatment with insulin 65 days after induction of diabetes resulted in a glucose-dependent decrease in IGF-I receptor mRNA. Chronic hyperinsulinemia with near normoglycemia did not change gene expression of either IGF-I or IGF-I receptor. The studies suggest that glucose levels per se, independent of insulin levels, play an important role in the regulation of IGF-I receptor gene expression in the chronically diabetic kidney. Furthermore, kidney hyperperfusion in chronic diabetes is coupled with the increase in IGF-I receptor mRNA, despite normal kidney IGF-I levels.

Eventration of the diaphragm due to phrenic nerve injury caused by intercostal drainage.

Acquired eventration of the diaphragm is caused by injury to the phrenic nerve with resultant paralysis and elevation of the entire diaphragm. In this reported case, damage to the phrenic nerve was caused by an intercostal drain. This has not been previously reported.

Practice and theory of "delayed" embolectomy. A 22-year perspective.

A study was made of delayed embolectomy in 45 patients (55 limbs). In 5 patients (11%) the cause of arterial embolization was rheumatic heart disease, and 40 patients (89%) suffered from atherosclerotic cardiovascular disease. The study was divided into 3 phases: I (1960-1964), II (1965-1974) and III (1975-1981). In phases II and III surgery was carried out using the Fogarty catheter technique. In 5 patients the embolus was located in the upper extremity. Seven patients died and 8 major amputations were performed within 30 days of surgery. Use of the Fogarty catheter technique and persistent anticoagulant therapy effected 71.8% limb salvage in phase II and 91.6% limb salvage in phase III. Successful revascularization was achieved in 70.9% of the limbs in which peripheral emboli had occurred on an average of 2.7 days prior to surgical intervention. A theoretical basis for the late development of the acute embolic onset is presented.

Arterio-venous fistula in the lower limb in consequence of Fogarty balloon catheter embolectomy. Case report and review of the literature.

Arterio-venous fistula following Fogarty catheter embolectomy is a rare but dangerous complication. The case of a male patient in whom such a fistula was repaired surgically is described. Aggressive approach in the treatment of this severe condition to prevent unnecessary limb loss is advocated. The pertinent literature is reviewed.

Preoperative dipyridamole-thallium scanning, selective coronary revascularization and long-term survival in patients with critical lower limb ischemia.

BACKGROUND: A large proportion of patients with critical limb ischemia have advanced, often asymptomatic coronary artery disease which is associated with increased perioperative risk and decreased long-term survival. METHODS: We evaluated retrospectively the short and long-term effect of routine dipyridamole-thallium cardiac scanning (DTS) and selective coronary revascularization in 113 consecutive patients who were scheduled for revascularization of the lower extremity. RESULTS: DTS was abnormal in 60 (53.1%) patients and demonstrated a moderate-severe reversible defect in 26 (23.0%) patients. On the basis of DTS and clinical evaluation 33 (29.2%) patients were referred for coronary catheterization. Of these, 9 underwent PTCA and 4 underwent coronary artery bypass, without complications. Surgical revascularization of the limbs was performed in all but two patients. Two (1.8%) patients died postoperatively, three (2.7%) sustained nonfatal postoperative myocardial infarctions. None of the patients who underwent preoperative coronary revascularization suffered a cardiac complication after the peripheral vascular operation. During mean follow-up of 31.7 months, 30 (28.0%) patients died. A moderate-severe reversible defect on DTS was the strongest predictor for shortened survival (Exp(b)=0.61, CI 95%=0.42-0.88; p=0.006). Patients who underwent preoperative coronary revascularization followed a survival curve approaching those without a reversible defect on DTS (mean survival 61+/-8 vs 63+/-4 months; NS) which was significantly better than those with such a defect who did not undergo coronary revascularization (mean survival 34+/-5 months; p=0.03). CONCLUSIONS: While the perioperative benefits of routine preoperative DTS screening in patients with critical limb ischemia, remain debatable, it provides an opportunity for identification and treatment of life-limiting coronary artery disease and improving survival.

Urgent abdominal aortic aneurysm repair in patients over the age 80.

We present three patients with successful surgical repair of abdominal aortic aneurysms with signs of imminent rupture in octogenarians. The patients presented with evidence of severe left ventricular dysfunction and reduced compliance either before or during surgery. Extremely cautious delivery of fluids and of after-load reducing agents was employed under the guidance of measurements of cardiac output and filling pressures from a pulmonary arterial catheter inserted prior to surgery.

Ultrasound-guided thrombin injection for the treatment of iatrogenic pseudoaneurysm of the femoral artery.

BACKGROUND: Pseudoaneurysm occurring after catheterization of the femoral artery is associated with significant morbidity. Percutaneous ultrasound-guided thrombin injection has recently emerged as a potential first-line therapy. OBJECTIVES: To evaluate the efficacy of this treatment in eight patients with iatrogenic femoral artery pseudoaneurysm. METHODS: After attempted treatment with external compression had failed, eight patients with iatrogenic femoral artery pseudoaneurysm were treated with thrombin injection. Treatment performed between 2 and 9 days following arterial puncture. The study group comprised seven males and one female ranging in age from 23 to 89 years (median 70). Seven had undergone cardiac catheterization with or without intervention, and five were receiving antiplatelet and/or anticoagulant drugs. Arterial pseudoaneurysm resulted from femoral vein catheterization in one patient. Using a sterile technique and real-time Doppler ultrasound guidance, a dilute solution of bovine thrombin (average dose 250 units, range 100-600), was slowly injected directly into the pseudoaneurysm until cessation of flow was seen. Patients were allowed to walk within 2 hours of the procedure and were followed up clinically and by color Doppler ultrasound during the admission. RESULTS: Cardiac catheterization had been inadvertently performed via the superficial or profunda femoris arteries in four of the eight patients. Thrombin injection was initially successful in all eight patients without complication. Thrombosis occurred immediately in every case. Early recanalization of pseudoaneurysm occurred in one patient despite repeat thrombin injection and attempted ultrasound-guided compression. He eventually required surgical repair. The final success rate was 87.5% (7/8). CONCLUSION: Faulty puncture technique is an important risk factor for the development of post-catheterization femoral artery pseudoaneurysm. Ultrasound-guided thrombin injection is a safe, rapid, well-tolerated, inexpensive and successful therapy. If initial external compression with a sandbag fails to result in thrombosis of the pseudoaneurysm then thrombin injection should be considered as first-line therapy. If unsuccessful, it does not preclude the use of alternative treatment modalities. Further study is necessary to assess the long-term effects of thrombin injection.

[Surgical treatment of chronic mesenteric ischemia].

A 44-year-old woman with chronic abdominal pain and weight loss is presented. 1 year after onset of symptoms and following multiple diagnostic procedures, angiography revealed high grade stenosis of the celiac and superior mesenteric arteries at their origins. Bypass grafts of Goretex were implanted from the infrarenal aorta to both arteries beyond the narrowed segments. 1 year after surgery the patient has regained her weight and is feeling well.

[Treatment of concomitant coronary and carotid disease].

The optimal surgical treatment for concomitant carotid and coronary artery disease is controversial. Between 1991 and 1995 we performed 34 procedures for combined disease of the carotid and coronary arteries. The first 8 operations were carotid endarterectomies followed by coronary artery bypass grafting (staged procedure). The next 26 operations were performed during a single anesthesia (combined procedure). The patients were 28 men and 6 women, aged 58-81 years (mean 68). 80% were in functional class III or IV. In 40% ventricular function was moderately or severely reduced. There was an average of 3.6 grafts per patient, and in all except 3 patients the left internal thoracic artery was used as a conduit for coronary artery bypass grafting. 30% had symptomatic carotid stenosis; there was no perioperative mortality. In the staged procedure group, 2 patients had postoperative cardiac complications: in 1 acute coronary insufficiency and acute myocardial infarction in the other. 1 had postoperative, transient, amaurosis fugax. In the combined procedure group, 1 had a myocardial infarction and 1 a minor occipital stroke. During follow-up, 1 patient died 4 months after operation of myocardial infarction, and 1 had a minor stroke. The results suggest that the combined procedure is safe and carries low risk of both mortality and morbidity. Whenever cardiac disease is stable and there is no main coronary artery disease, a staged procedure should be considered. In any other situation we continue to perform the combined procedure.

"Delayed rupture of the spleen" or delayed diagnosis of the splenic injury?

Splenic rupture is the most frequent intraabdominal injury following blunt abdominal trauma. Massive hemorrhage commonly occurs from injuries to this friable vascular organ. The mortality rate from simple splenic rupture is 1%. Delayed diagnosis of a ruptured spleen increases the rate to 10%. During 1964-79, 293 patients underwent splenectomy for blunt splenic injury, of whom 278 were operated on within 24 h. All had typical signs of splenic lacerations with intraperitoneal bleeding from the time of injury. Fifteen patients were operated on more than 48 h after sustaining the injury. A detailed analysis of these 15 patients revealed that in only three did the evidence support delayed hemorrhage following traumatic rupture of the spleen. In the other 12 patients, there was a delay in recognition of the intraabdominal injury, almost entirely the result of "diagnostic error." Careful clinical inquiry and peritoneal lavage are the mainstays of early diagnosis and therapy and should help to eliminate any delay in the diagnosis of a ruptured spleen.

Six-year experience with bovine arterial graft for hemodialysis.

During the last six years 29 bovine arterial grafts were implanted in 21 patients. A total of 186 angioaccesses had been performed on these patients prior to the insertion of bovine graft. Nineteen grafts (65.5%) are still patent with a mean patency time of 43 months. Ten grafts (34.5%) failed, the main cause of failure being infection. The cumulative patency of failed grafts was 46 months.

Extrathoracic approach in surgical treatment of subclavian steal.

Between 1979 and 1985 11 selected patients underwent axilloaxillary and carotid-subclavian bypass grafting [dacron or Gore-Tex (USA), 8 mm inner diameter]. Nine patients had lesions in the left subclavian artery and two patients presented with innominate artery obstruction with subclavian-carotid recovery phenomenon. All patients were symptomatic before surgery, and all were relieved of both cerebrovascular and upper extremity ischemic symptoms following surgery. Early graft patency has been excellent. There has been no mortality or serious postoperative complications. Two patients developed late graft thrombosis with recurrent ischemia of the left upper extremity, but there were no neurological symptoms. There has been a follow-up period of up to 6.5 years (mean 38.4 months.) It would appear that the appropriate extrathoracic route of revascularization is the procedure of choice for symptomatic patients with subclavian steal and subclavian-carotid recovery phenomenon.

A life-threatening complication of the infusion pump.

Serious disturbances in respiration and venous return developed in 2 infants in whom infusion into a central vein was controlled by a peristalic pump. The effects were the result of extravasation which led to build-up of pressure in the medistinum.