Factors impacting functional health and resource utilization following abdominal aortic aneurysm repair by open and endovascular techniques.

We assessed the impact on patient outcomes of comorbidities and type of aneurysm repair, open vs. endovascular aortic repair (EVAR). Functional health status was measured prospectively using the Short Form 36 (SF-36) Health Survey. Length of stay (LOS) and need for postdischarge resources (nursing and rehabilitation) were compared between groups. We reviewed the records of 218 patients (126 open, 92 EVAR) who underwent intervention between 1998 and 2003. The SF-36 was completed preoperatively and at intervals ranging from 2 weeks to 1 year after intervention. To identify factors impacting outcome, univariate and multivariate analyses were performed. Overall mortality was 1.9%: 3.2% for open repair and 0% for EVAR (p = 0.13). Physical and mental health were higher during the 3 months following EVAR compared with open repair: physical function (PF) (65.2 +/- 4.1 vs. 54.0 +/- 4.1), vitality (VT) (55.5 +/- 2.5 vs. 44.9 +/- 3.4), and emotional role (ER) (74.9 +/- 5.0 vs. 51.4 +/- 6.7) (analysis of variance p < 0.05). Women following EVAR had decreased physical summary scores (PSS) (34.8 +/- 2.5 vs. 40.4 +/- 1.1, p < 0.05) compared with men postprocedure despite no difference preoperatively. Congestive heart failure (CHF) was an independent factor that negatively impacted PF, body pain (BP), and PSS. EVAR was associated with improved VT and ER. Differences among open repair and EVAR diminished over time. LOS (in days) was greater for open vs. EVAR (9.2 +/- 0.78 vs. 2.0 +/- 0.17) and in women following both open (11.8 +/- 1.5 vs. 8.0 +/- 0.9) and EVAR (3.2 +/- 0.9 vs. 1.8 +/- 0.1) procedures (p < 0.05). Factors that adversely affected LOS were open repair, age, renal insufficiency, pulmonary disease, CHF, and female gender. Following EVAR, patients were less likely to require home care or transfer to a rehabilitation facility than after open repair (14.1 vs. 36.0%, p < 0.05). Women were significantly more likely to require postdischarge care after open repair (48.7 vs. 30.1%) and EVAR (41.7 vs. 10.0%) (p < 0.05). Logistic regression identified female gender, open repair, advanced age, and pulmonary disease as independent predictors of need for postdischarge care. Those patients undergoing abdominal aortic aneurysm (AAA) repair by open technique (compared to EVAR) had significantly impaired functional health with regard to PF, VT, and ER in the first 3 months after surgery. CHF and hypertension also significantly impaired individual functional health scores. Of significance was that female gender was associated with increased LOS and increased utilization of postdischarge nursing and rehabilitation resources following both open and endovascular surgery for AAA.

Resource utilization and outcomes: effect of transfer on patients with ruptured abdominal aortic aneurysms.

We evaluated the transfer of patients with the diagnosis of a ruptured AAA (rAAA) from community centers to a tertiary care center. Our purpose was to identify factors associated with mortality and outcomes following the open repair of rAAA and to evaluate the differences between transferred and nontransferred patients. All patients who underwent repair of rAAA at our institution between 1995 and 2002 were retrospectively reviewed. Univariate and multivariate analysis was performed to identify patient specific factors on presentation and intraoperatively. Fifty-two patients underwent repair of rAAA, 20 patients were transferred to our institution. The overall mortality rate was 67%. The mortality rates for nontransferred and transferred groups were 69% and 65%, respectively. The incidence of mortality within 24 hr of surgery was significantly higher in the patients who were not transferred, 10 vs. 41% (p < 0.05). Patient-specific factors assessed for impact on survival by logistic regression included decreased body temperature on arrival to our institution (p = 0.02) and free rupture (p = 0.05). Of intraoperative factors tested, low systolic blood pressure was significantly associated with mortality (p = 0.05). No difference in total length of stay was noted. Transfer patients' length of stay in the intensive care unit was significantly greater than that of nontransferred patients (18.8 +/- vs. 7.3 +/- days, p < 0.05). The difference in ICU cost was dollar 36,000 among groups. We found the acceptance of transfer patients from community centers with rAAA did not adversely affect patient survival. Transferred patients had an over twofold increases in ICU days used. The identification of hypothermia was the single independent factor associated with poor survival and may be a marker for transfer selection. Given reduced reimbursements and increased utilization, tertiary care centers will need to consider the economic ramifications of accepting transfer patients with rAAA.

Prevention of thrombosis of central venous catheters.

All central venous catheters develop a fibrin sheath and clot formation which can cause pulmonary emboli, especially when the catheter is withdrawn. The degree of fibrin sheath and clot is dependent not on the length of residence in the vein but related more to the type of catheter material. A study was performed placing the more commonly used catheters in arteries and veins of canines for two weeks and then evaluating the volume of sheath and thrombus. Polyurethane catheters were the most thrombogenic, whereas polyurethane coated with hydromer was the least thrombogenic, followed closely by silicone catheters. Polyvinyl chloride catheters were intermediate in their thrombogenic activity.

Distal tibial artery thrombectomy in acute limb ischemia.

During the past two years, in cases of infrapopliteal embolic occlusion not retrievable through the femoral approach, we have used distal tibial thrombectomy in preference to a direct approach via the popliteal artery. Distal tibial thrombectomy was done in seven extremities in six patients with excellent results. Only one extremity required subsequent amputation. There were no mortalities. This represents a limb salvage rate of 85%.

Evaluation of central venous catheter thrombogenicity.

Four studies were performed to evaluate the thrombogenicity of different central venous catheter materials. Two of these studies consisted of evaluating the amount of platelet deposition on different catheter materials, firstly in vitro and then in vivo using dogs. In these studies, 51-chromium was used to label the platelets. In the following study, the volume of clot and the degree of fibrin sheath were determined by placing catheters in both arteries and veins of dogs for two to four weeks before removing the vessels and performing a quantitative analysis. For the fourth study, indium labelled platelet deposition with scintillation counting was performed on six dogs in whom catheters had been placed in the femoral and carotid arteries. The vessels in three of these animals were removed 48 hours after imaging was completed to correlate the scintigraphic findings with a quantitative analysis of the clot and fibrin sheath on each catheter. There was a high degree of correlation between all these studies. The most consistently thrombogenic catheter material was polyurethane, and the least thrombogenic catheter material was polyurethane coated with hydromer. Silicone was the next least thrombogenic material examined.

Popliteal arteriovenous fistula following meniscectomy.

A case of arteriovenous fistula between the popliteal artery and vein after injury during medial meniscectomy is presented. The diagnosis was made on the fifth postoperative day by angiography, and a successful reconstruction of the artery and vein was accomplished by primary anastomosis of the artery following resection of the damaged part; the vein was closed by lateral venorrhaphy.

The affinity of platelets for the subendothelium.

It is known that platelets adhere to subendothelial tissues, but it is not clear as to whether this results in thrombus formation. To study this question, 94 arterial specimens in dogs were randomly treated, either by balloon stripping which exposed the subendothelium (Group I) or by endarterectomy, which exposed the media (Group II). Platelets tagged with 51Cr were injected into some of the animals and the degree of adherence to the vessel wall measured. In the rest, the thrombosis rate was measured at 48 hours. It was shown that the platelets tend not to adhere to the subendothelium in great numbers. The thrombosis rates were 8.6 per cent in Group I compared to 47.8 per cent in Group II. The conclusion drawn from these results was that the subendothelium was antithrombogenic and that this layer should be preserved at vascular anastomoses to discourage platelet adherence and thrombosis.

Intraoperative angiography.

Intraoperative angiograms were performed on 131 patients. There were 23 aortoiliac procedures (Group I); 20 aortofemoral procedures (Group II); 25 femoral artery reconstructionellaneous operative angiograms (Group V) were included; examples of this group were renal artery and brachial artery reconstructions. Ten intraoperative carotid angiograms comprised Group VI. Twenty-three patients (17.5%) showed abnormalities which required correction. These were the presence of thrombus in 11 (47.8%) and anastomotic stricture in nine (39.1%); the remaining 13.1 per cent consisted of one kinked graft, one vessel disruption, following embolectomy, and one false aneurysm. The incidence of defects was 4.3 per cent in Group I; 15 per cent in Group II; 16 per cent in Group III; 21.6 percent in Group IV, and 25 per cent in Group V. A 30 per cent incidence was found in Group VI. Technical defects in vascular reconstructions are revealed by intraoperative angiography in a significant number of cases and their incidence is directly related to the size of the vessel being operated on. Recognition and repair of these defects should result in a reduction in the rate of early occlusion.

Intermittent claudication: its natural course.

Of more than 600 patients seen for intermittent claudication by this group and not primarily considered for surgery, 104 had angiographic studies and are the basis for this report. The follow-up period varied from 6 months to 8 years, with a mean of 2.5 years. Classification by severity of claudication revealed 33 with less than one block, 36 with two blocks, and 35 with two or more blocks, foot, calf, or thigh claudication. Eighty-two remained stable or improved and 22 worsened. Of the 22 who worsened, 16 had only worsening of claudication (six of them requiring arterial reconstruction) and six progressed to gangrene and required amputations. Of the 82, 66 either had marked improvement of claudication or remained sufficiently stable not to require any operative intervention. Sixteen required arterial reconstruction for persistent, intolerable, or incapacitating claudication. Five of the six amputees were from the less than one half block claudication group. Angiographic studies were significant only in relation to the below-knee runoff in that three of 25 with less than one vessel runoff, two of 23 with one to two vessel runoff, and one of 56 with two to three vessel runoff came to amputation, regardless of the pattern of more proximal arterial occlusions. The study suggests that intermittent claudication is relatively benign, with only 5.8 percent coming to amputation in a 2.5 year mean follow-up. Prognosis is determined by the severity of below-knee arterial involvement and apparent inability to compensate for ischemia via the collateral circulation since only 12.5 percent of those with the most pronounced involvement came to amputation.