Cost comparison of aortic aneurysm endograft exclusion versus open surgical repair.

BACKGROUND: Shrinking health care resources impose a requirement to evaluate new technology for cost as well as clinical effectiveness. We studied an initial clinical experience with endograft treatment (EAG) of abdominal aortic aneurysm (AAA) at the beginning of an endovascular program in comparison with open surgical repair (OSR), which had been in use for decades. METHODS: From March 1997 to April 1998, the utilization of hospital resources, actual cost, clinical descriptors, and treatment outcomes were recorded for two contemporaneous groups, each having 16 consecutive patients with AAA, treated with either EAG or OSR. Subjects were not randomized; EAG treatment was based on predetermined exclusion/inclusion criteria. Statistical comparison was by either Fisher's exact test or the Wilcoxon rank sum test. RESULTS: There were no differences between OSR and EAG in age, gender, AAA size, smoking status, diabetes, ischemic heart disease, history of coronary artery bypass grafts, previous vascular surgery, or other comorbidity. There were no deaths in either group. Patients treated by EAG procedure had significantly lower length of hospital stay, length of stay in intensive care unit, time in operating room, and cost of operating room without graft (P <0.05). Cost of operating room with graft was less in OSR group (P <0.001). In-hospital imaging costs specific to the EAG procedure were $1,370.45 +/- $66.92 (range $911.58 to $1,826.76). Total costs were not significantly different between the OSR and EAG, $12,714.19 +/- $1,115.52 and $12,904.99 +/- $494.69, respectively (P = 0.26). CONCLUSIONS: Total hospital cost is not different for the two treatments studied despite differences in experience with their use. Endograft treatment utilizes significantly less hospital resources than open surgical repair. The endograft prosthesis contributes a significant cost increment that may decline with expanded use.

Carotid arterial ultrasound scan imaging: A direct approach to stenosis measurement.

PURPOSE: Management decisions regarding carotid artery disease are critically dependent on stenosis but have been made difficult because of conflicting methods used to determine such stenosis. The increasing use of duplex ultrasound scanning has conventionally depended on Doppler velocity measurement, an indirect method for calculating carotid stenosis. Recent technical advances have improved the quality of B-mode/color-flow ultrasound scan imaging (USI). We tested prospectively whether USI was clinically effective as the primary criterion for estimating carotid stenosis. METHODS: Transverse and longitudinal USI, Doppler velocity, and arteriography data were obtained sequentially and independently for 713 carotid bifurcations. The internal carotid artery (ICA) residual lumen, the local outer diameter at the stenotic site, and the diameter distal to the bulb were measured in a representative USI longitudinal section. The peak systolic velocity and the end diastolic velocity (EDV) were measured at the stenosis. Local stenosis as determined with USI was compared with the x-ray arteriographic clinical radiology interpretation (XRI). As the primary method, radiologists compared the residual lumen with the distal ICA diameter, as recommended by the North American Symptomatic Carotid Endarterectomy Trial and the Asymptomatic Carotid Atherosclerosis Study. Analysis was by means of the USI positive predictive value (PPV) and negative predictive value (NPV) of the XRI findings, with the assumption that 80%, 70%, and 60% local stenosis with USI related to 70%, 60%, and 50% stenosis with XRI, respectively. RESULTS: All 56 ICA occlusions as determined with USI were confirmed with XRI. When the USI showed 80% to 99% stenosis, the PPV of the XRI showing 70% to 99% stenosis was 94% (116/123). Two ICAs that were shown to be severely diseased with USI appeared to be occluded with XRI. For <50% stenosis shown with USI, the prediction of <50% stenosis shown with XRI was 94% (253/269). For borderline stenosis in the 50% to 79% range with USI, the addition of velocity criteria to USI data improved both the PPV and the NPV. In the range of 70% to 79% stenosis with USI, the PPV improved from 82% (76/93) to 91% (53/58) for the subgroup with an EDV of more than 80 cm/s. For the range of 60% to 69% stenosis with USI, the PPV improved from 75% (71/95) to 95% (21/22) for the subgroup with an EDV of more than 80 cm/s. In the range of 50% to 59% stenosis with USI, the NPV improved from 69% (53/77) to 93% (14/15) for the subset with a peak systolic velocity of less than 100 cm/s. CONCLUSION: On the basis of the USI data alone, a prediction of arteriographic findings was possible at the 95% level for occlusion and severe stenosis and for ruling out hemodynamically significant stenosis. The addition of velocity data improved prediction in borderline degrees of stenosis. USI was effective for quantifying clinically significant degrees of stenosis.

Lower extremity arterial evaluation: are segmental arterial blood pressures worthwhile?

PURPOSE: Physiologic observations with blood flow waveform analysis and pressure measurements can document the severity of lower extremity arterial disease. Segmental blood pressures (SEGPs) taken at the thigh, calf, and ankle are commonly used, but their utility has seldom been studied. We quantified improvements in accuracy compared with arteriography when ankle pressures alone (ABI) or SEGP data were added to velocity waveforms obtained by Doppler ultrasound. METHODS: Continuous-wave Doppler velocity waveforms were recorded at common femoral (CFA), popliteal (POP), and dorsal pedal and posterior tibial (TIB) arterial levels. Systolic SEGP data were obtained with appropriately sized upper thigh, upper calf, and ankle cuffs. Waveforms, waveforms plus ABI, and waveforms plus SEGP data from 81 patients were randomly interpreted by 14 technologists or physicians from four institutions blinded to clinical and arteriographic data. Arteriograms were assigned negative or significant, severe (>75% diameter stenosis) values for four segments: iliofemoral (CFA), superficial femoral (SFA), popliteal (POP), and infrapopliteal (TIB) arteries. A total of 9072 segmental interpretations were analyzed. RESULTS: Compared with arteriography, the accuracy of waveform analysis was 83% for severe disease at and proximal to the CFA, 79% for SFA disease, 64% for POP disease, and 73% for TIB disease. Adding ABI improved the accuracy significantly (p < 0.01) to 88% (CFA), 86% (SFA), 70% (POP), and 85% (TIB). Accuracy was inferior when SEGP data replaced ABI: 86% (CFA), 85% (SFA), 70% (POP), and 80% (TIB). CONCLUSIONS: ABIs significantly improved Doppler waveform accuracy at all levels. Compared with ABI, the addition of segmental pressure to waveform data failed to improve accuracy. Pressure measurements above the ankle may lack cost effectiveness and clinical utility.

Gender bias in use of venous ultrasonography for diagnosis of deep venous thrombosis.

PURPOSE: We observed that ultrasound examinations for deep venous thrombosis (DVT) were more frequently requested for women than for men in our vascular laboratory serving a general outpatient population and referral 774-bed hospital. Because existing literature presents conflicting information about sex differences in occurrence of DVT, we investigated correlation in our population with positive ultrasound study results and risk factors for DVT. METHODS: In 13 months, 2055 ultrasound examinations for DVT were requested. Of these, 300 patients (15%) were categorized in four subgroups: 75 ultrasonography-negative men, 75 ultrasonography-negative women, 75 ultrasonography (DVT)-positive men, and 75 ultrasonography (DVT)-positive women for risk factor analysis. RESULTS: Women comprised 64% (1311 of 2055) and men 36% (744 of 2055) of ultrasound examinations requested, but men had significantly higher incidence of DVT-positive ultrasonography results (101 of 744 [14%]) compared with women (118 of 1311 [9%]) (p = 0.002 by chi-square testing). There were no significant sex differences in conventional DVT risk factors and no difference in aggregate number of risk factors. The anatomic distribution of DVT was the same in men as in women. Among those having negative ultrasonography results, significantly more outpatient examinations were performed in women (p = 0.018 by t testing). CONCLUSIONS: Gender bias exists in use of ultrasonography for diagnosis of DVT. The greater incidence of women undergoing venous ultrasonography is not explained by higher prevalence of DVT risk factors or of higher occurrence of positive ultrasound examination results. Further investigation is needed to determine whether these differences indicate underuse of ultrasonography in men or overuse in women.

Deep vein obstruction and leg swelling caused by femoral ganglion.

We present a case of a rare ganglion cyst originating from the hip joint and compressing the common femoral vein producing signs and symptoms that mimicked a deep vein thrombosis. Excision of the mass promptly restored normal venous return. This condition has not been previously reported in the English-language medical literature.

Carotid endarterectomy in the stroke patient: computerized axial tomography to determine timing.

Historically, patients with mild to moderate neurologic deficits lasting longer than 24 hours were believed to have sustained a completed stroke. They were followed up for 4 to 6 weeks and cerebral angiography was performed if indicated. CT scanning has identified a subset of these patients who have sustained a reversible ischemic neurologic deficit (RIND) rather than a completed stroke. The timing for angiography and surgery for this group has not been established. In an earlier study we found that 21% (4 of 19 patients) suffered a second stroke during the 4- to 6-week waiting period. To avoid this high rate of recurrence, we instituted an aggressive program of CT scan evaluation and surgical therapy for all "stroke patients" with negative CT scans. Two hundred forty-five patients were seen with a persistent neurologic deficit between July 1980 and December 1983. These patients underwent CT scans 1 and 5 days after the initial event. Of these 245 patients, 171 patients (70%) were found to have negative CT scans. Appropriate carotid lesions were found by arteriography in 110 (64%) of the negative CT scan group. There were 61 (55%) men and 49 (45%) women in this group. Eighty-five patients (77%) had previous neurologic symptoms or a cerebrovascular accident. Hypertension was present in 52% and diabetes mellitus in 30%. All 110 patients underwent carotid endarterectomy within 14 days (mean 10 days) of the initial onset of their neurologic deficit; these were all done with shunt protection. No patient suffered another neurologic deficit in the same territory within 30 days after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Distal bypass graft for limb salvage.

The use of "distal bypass grafts" in the lower extremity for limb salvage is controversial among vascular surgeons. Twenty-nine "distal grafts", defined as grafts with their distal anastomosis within 3 inches (7.5 cm) of the ankle malleoli, were performed. All patients selected for the procedure had an intact pedal arch in continuity with the grafted vessel and limited gangrene of the foot. The grafts consisted of 4 patients with grafts to the peroneal artery, 3 to the anterior tibial artery, 5 to the dorsalis pedis artery and 17 to the posterior tibial artery. Of the 29 grafts attempted, 22 (76%) continued to function from 6 months to 4 1/2 years postoperatively. The 22 successful grafts consisted of autogenous vein greater than 4 mm in diameter. Twenty-two limbs were salvaged by distal bypass more than 24 hours postoperatively were important prognostic indications. Careful attention to technique and the use of magnification were believed to be important aspects of successful graft construction.

Independent development of contractile properties and myosin light chains in embryonic chick fast and slow muscle.

1. The contractile speeds and tetanus/twitch ratios of the slow anterior latissimus dorsi (ALD) and fast posterior latissimus dorsi (PLD) muscles were studied during embryonic development and correlated with the type of myosin light chains present in these muscles as studied by one and two dimensional polyacrylamide gel electrophoresis. 2. At a time when the contractions of PLD were slow, i.e. in 15 day old embryos, the myosin light chains in this muscle were of the fast type. The slow contraction of this muscle may be due to incomplete and slow activation of the contractile elements. The tetanus/twitch ratio of muscles from 15 day old embryos is low and increases sharply with age. This increase could be due to the maturation of the internal membrane system, and occurs at about the same time as the increase in the speed of contraction. 3. ALD muscles contract slowly during all stages of development, although their tetanus/twitch ratio also increases with age. At 13 days they contain a mixture of fast and slow type myosin light chains and with increasing age the proportion of the slow type myosin light chains increases at the expense of the fast type. The slow time course of contraction of ALD is consistent with the presence of slow type myosin light chains. 4. The possibility that the synthesis of the slow type myosin light chains in ALD is induced by early motor activity in chick embryos is discussed.