Complications of percutaneous intra-aortic balloon pump use in patients with peripheral vascular disease.

Percutaneous intra-aortic balloon pump use may carry an increased risk for patients with peripheral vascular disease. To determine the incidence and types of associated complications, the medical records of 144 patients who underwent a total of 153 percutaneous intra-aortic balloon pump insertions were reviewed. Patients were divided into two groups. Group 1 was composed of 20 patients with a history of peripheral vascular disease. Group 2 was composed of 124 patients without such history; they underwent a total of 133 insertions. Nineteen major complications (12%) occurred, 12 in group 1 (60% of 20 insertions) and seven in group 2 (5% of 133 insertions). Major complications were further classified by their nature: embolic, occlusive, and technical. All three types of complications occurred more frequently in group 1. Embolic complications occurred more frequently in patients with aneurysms and proved the most lethal, with two of six deaths in group 1 resulting from this complication.

Indirect measurement of systolic blood pressure in the rabbit.

Long-term studies of rabbit blood pressure require a reliable method for repeated blood pressure measurements. Ideally, this method would be simple, noninvasive, and accurate over the range of anticipated blood pressures. To facilitate our own studies of rabbit carotid artery graft patency, we have developed a technique for the indirect measurement of systolic blood pressure in the rabbit that utilizes a photoplethysmograph sensor placed distal to an inflatable air bladder positioned over the central ear artery. We have compared measurements obtained with this method to direct measurements of aortic pressure and found a linear correlation.

Transaortic endarterectomy of renal visceral artery lesions in association with infrarenal aortic surgery.

The complexity of infrarenal aortic reconstruction increases when bypass grafts to revascularize associated renal and visceral arteries are needed. Lesions in these vessels, however, are usually limited to their aortic orifices and therefore are amenable to retroperitoneal transaortic endarterectomy. A combined infrarenal aortic reconstruction and transaortic endarterectomy of the renal/visceral vessels was used in 18 (16%) of 120 patients undergoing elective infrarenal aortic reconstruction over a 2-year-period. Transaortic endarterectomy was performed primarily for renal preservation in 11 patients with bilateral, high-grade renal artery stenoses and abnormal renal function (serum creatinine greater than or equal to 1.9 mg/dl). In seven patients transaortic endarterectomy was performed as a secondary procedure during the course of complex reconstruction of aneurysmal or occlusive aortic disease. Mean serum creatinine, which was elevated preoperatively in 14 (78%) patients (3.3 mg/dl), decreased significantly after the operation (2.0 mg/dl, p less than 0.01). A single death occurred in the 18 patients undergoing transaortic endarterectomy. Renal function preservation can be achieved by renal revascularization in patients with bilateral renal artery stenoses and decreased renal function. The retroperitoneal approach to aortic reconstruction and the use of transaortic endarterectomy allows correction of most renal/visceral vessel involvement in complex aortic revascularization procedures.

Combined epidural and general anesthesia in aortic surgery.

The perioperative course of 144 consecutive patients undergoing aortic reconstructive surgery was studied to assess the potential benefit of employing a combined epidural and light general anesthesia technique. A group of 67 patients had general anesthesia alone (GA), while in the group of 77 remaining patients, a combined epidural and general anesthesia (Epi-GA) was employed. The two groups were similar in regards to age, medical risk factors, preoperative assessment of cardiac and pulmonary function, and type of surgical reconstruction. There was no significant difference in the anesthetic, operative time, or operative fluid requirements between the two groups. There was a lower rate pressure product in the Epi-GA group during aortic cross clamping (P less than 0.05). More patients in the GA group required a prolonged ventilatory support (P less than 0.05) and a high parenteral narcotic administration (P less than 0.025) during the first 48 hours. While the mortality rate was similar for the two groups (3.0% for GA group vs 5.2% for Epi-GA group), there was a higher percent of postoperative pulmonary complications observed in the GA group (7.6%) compared to the Epi-GA group (2.6%). By facilitating early extubation and a decreased need for systemic narcotics in the early postoperative period, Epi-GA may be beneficial in the high risk pulmonary patient undergoing aortic reconstruction.

The value of computed tomography in the management of symptomatic abdominal aortic aneurysms.

The use of computed tomographic (CT) scanning in the diagnosis of ruptured abdominal aortic aneurysm is controversial because the delay created by the procedure, it has been argued, may increase overall mortality. However, if emergency surgery can be avoided in the medically compromised patient, surgical results may improve. To assess the value of CT scanning, we studied the 1983 to 1988 records of 65 hemodynamically stable patients with abdominal aortic aneurysms, who underwent diagnostic CT scanning for acute abdominal or back pain. Twenty-one patients had a history of severe cardiac, renal, or pulmonary disease. The average duration of the examination was 63 minutes; no episodes of hypotension occurred. Subsequently, 17 of 18 patients with ruptured aneurysms had emergency surgery, with 31% morbidity and 29% mortality. Of 44 patients found to have nonruptured aneurysms, 13 had other causes for their pain, nine were not considered surgical candidates, and 24 had elective aneurysmectomies, with 8% morbidity and 0% mortality. In three patients CT scanning excluded the diagnosis of aneurysm. Additional information provided by CT scanning enhanced the safety of the perioperative management of four patients with rupture and 14 without. In conclusion, the delay imposed by obtaining a preoperative CT scan in patients with possible ruptured aneurysm did not adversely affect patient outcome, and the information obtained from it aided significantly in both preoperative and intraoperative management.

The early and late responses of the arterial wall to graft placement.

The relationship between the early smooth muscle cell proliferative response (SMC-PR) to injury and the later development of myointimal hyperplasia (MIH) complicating arterial bypass grafts remains unclear. In the present study, the early SMC-PR and the later MIH induced by a 2-mm-diameter PTFE graft placed in a rabbit carotid were compared with the response induced by an autogenous artery (AA) graft in the contralateral carotid. The early SMC-PR was measured in the proximal and distal arterial segments 5 days after graft placement by in vivo labeling with [3H]thymidine to determine the DNA specific activity (DNA-SA). The later anastomotic MIH was measured 16 and 32 weeks postgrafting by calculating the intimal/medial ratio. There was a marked and similar increase in the early SMC-PR noted with both the AA and the polytetrafluoroethylene (PTFE) grafts. The distal segments demonstrated a significantly higher DNA-SA when compared to the proximal in both AA- and PTFE-grafted arteries. There was a moderate degree of anastomotic MIH noted in chronic grafts; however, a regression in intimal thickening was observed over time in the AA-grafted arteries, while the distal anastomosis of the PTFE-grafted vessels demonstrated a continuous progression of the MIH process. The early SMC-PR may abate in arteries grafted with autogenous grafts, but there is a persistent proliferative response at the distal anastomosis associated with synthetic grafts.

Alternative procedures to aortobifemoral bypass grafting.

The outcome of 175 bypass procedures performed on 174 patients with symptomatic aortoiliac occlusive disease during a five-year period were analyzed. Fifty-nine patients underwent a standard aortofemoral bypass and 116 patients underwent one of three alternative procedures consisting of femoro-femoral, iliofemoral, or axillofemoral bypass. The operative stress, morbidity, mortality and long-term results were compared. Although the aortofemoral group had a higher three-year cumulative patency rate (89% vs 81%), the alternative procedure group had a lower operative mortality (1.8% vs 7%). In addition, the patients in the alternative procedure group were slightly older, had a higher percentage of procedures performed for limb salvage, and had a less optimal run-off status, yet the complication rate was significantly less than that of the aortofemoral group (p less than 0.05). The use of these alternative procedures should be considered for patients with symptomatic aortoiliac disease, who represent a moderate operative risk as well as those in a high risk category.

An animal model for small-diameter arterial grafts.

A rabbit model was developed to study small-diameter arterial grafts. A total of 158 2-mm-diameter polytetrafluoroethylene (PTFE) grafts and 35 autogenous carotid artery (AA) grafts were interposed in the carotid arteries of New Zealand white rabbits. A pilot study of 16 PTFE grafts used to develop operative and anesthetic techniques had a 20% mortality and 38% early (less than 2 day) thrombosis rate. Subsequent to the pilot study 177 grafts were placed and a 92% postoperative survival with 100% AA graft patency and 93% PTFE graft patency at 2 weeks was observed. AA grafts followed beyond 16 weeks continued to have 100% patency, while PTFE grafts began to show increased failure. Closure was found to be due to the development of anastomotic myointimal hyperplasia.