Absence of proximal neck dilatation and graft migration after endovascular aneurysm repair with balloon-expandable stent-based endografts

OBJECTIVE: Proximal neck dilatation (PND) and/or endograft migration with the subsequent development of type I endoleak is a significant cause of late endograft failure after endovascular abdominal aortic aneurysm repair (EVAR). Although there are numerous reports examining PND in patients receiving endografts that use self-expanding stents (SES) for proximal fixation, there are no such reports for patients treated with endografts that use balloon-expanding stents (BES). The purpose of this study was to investigate PND and endograft migration after EVAR with BES endografts. METHODS: We retrospectively reviewed all charts and all serial computed tomographic scans available for patients who underwent EVAR with a BES endograft (surgeon-made, aortounifemoral polytetrafluoroethylene graft with a proximal Palmaz stent) between August 1997 and October 2002. Only patients with longer than a 12-month follow-up were analyzed. Neck diameter was measured at the level of the lowest renal artery and at 5 mm below it. PND was defined as neck enlargement of 2.5 mm or more. To assess endograft migration, the distance between the superior mesenteric artery and the cranial end of the BES was measured. Stent migration was defined as a change of 5 mm or more. RESULTS: A total of 77 patients received this device during the study period. The technical success rate was 99%. The 1-, 3-, and 5-year survival was 66%, 48%, and 29.5%, respectively. Complete serial computed tomographic scans were available in 41 of the 48 patients who survived 12 months or longer after the operation. The mean follow-up period for these patients was 31 months (range, 12-66 months). The maximum aneurysm diameter was either unchanged or decreased in 35 patients (85%). The immediate postoperative proximal neck diameter was 19 to 29 mm (median, 24 mm). This was unchanged at the latest follow-up. None of the patients had significant PND. The cranial end of the BES was located in the area between 14 mm proximal and 36 mm distal to the superior mesenteric artery (median, 6 mm). None of the patients developed significant endograft migration. CONCLUSIONS: Neither PND nor endograft migration was observed with the BES endograft. The nature of the SES may be responsible for the observed neck dilatation and device migration after EVAR with SES endografts. This study suggests that BES may be a better fixation method for EVAR.     

Influence of type II endoleak volume on aneurysm wall pressure and distribution in an experimental model

OBJECTIVE(S): We have previously shown that type II endoleak size is a predictor of aneurysm growth after aortic endografting. To better understand this observation, we investigated the influence of endoleak size on pressure transmitted to the aneurysm wall and its distribution within the aneurysm sac. METHODS: In an ex vivo model, an artificial aneurysm sac was incorporated within a mock circulation comprised of rubber tubing and a pulsatile pump. Three strain-gauge pressure transducers were placed in the aneurysm wall at different locations, including the site of maximum aneurysm diameter. The aneurysm was filled with either human aneurysm thrombus or dough that mimicked thrombus and simulated type II endoleaks of varying volumes (1 to 10 mL) were created. Aneurysm wall pressure (AWP) measurements were recorded at mean arterial pressures (MAPs) of 60, 80, and 100 mm Hg. Correlation coefficients ( r ) and analysis of variance were used to assess the relationship between endoleak volume and AWP. RESULTS: Increasing endoleak volume '3 cm 3 resulted in proportionally increased AWP at all levels of MAP and at all sites, with highest pressures recorded at the site of the maximum aneurysm diameter (r = 0.83 when MAP = 100 mm Hg; r = 0.85 when MAP = 80 mm Hg; r = 0.88 when MAP = 60 mm Hg; P < .001). AWP plateaued when the endoleak volume was >3 cm 3 . Pressure distribution within the sac was not uniform. Although the difference was within +/-10%, statistically significant higher AWPs were observed at the site of maximum aneurysm diameter (P <.001). AWP also correlated with MAP. CONCLUSIONS: Increasing type II endoleak volume results in proportionally higher AWP, which is greatest at the site of maximum aneurysm diameter. This study confirms the clinical observation that type II endoleak volume and MAP may be important predictors of aneurysm expansion. CLINICAL RELEVANCE: Our experimental model of a type II endoleak revealed that endoleak size is a significant factor that influences the magnitude of pressure transmission into the aneurysm wall. Increasing volume of the endoleak nidus was associated with proportionally higher aneurysm sac pressures. This mechanism may, in fact, account for the increased risk of aneurysm expansion observed in our clinical experience, thereby suggesting the need for more aggressive surveillance and possibly earlier intervention for patients with larger endoleaks.     

Infrapopliteal Angioplasty for Limb Salvage in the Setting of Renal Failure: Do Results Justify Its Use?

Multiple reports advocate the use of infrapopliteal angioplasty for limb salvage; however, its utility in the setting of renal failure is unclear. We performed angioplasty, rather than bypass, for tibial stenoses or occlusions <3 cm on 90 limbs of 79 patients (64.4% male, mean age 67.2 years), all with ischemic ulcer. Seventy (77.8%) had diabetes mellitus and 16 (17.8%) had end-stage renal disease (ESRD). Mean follow-up was 14.3 months (range 0.3-45). Associated femoropopliteal revascularization was required in 28 (31.0%) limbs. Primary angiographic success was achieved in 83 (92.2%) limbs. Residual stenosis or thrombosis occurred in two and five limbs, respectively. Dissection occurred in six limbs, all successfully treated with stent placement. Ulcer healing occurred after initial angioplasty in 41 (55.4%) non-ESRD and four (25%) ESRD limbs. Subsequent revascularization procedures were required in 21 (23.3%) limbs, including six bypasses and 15 repeat angioplasties, of which three underwent subsequent bypasses. Major amputation was required in 11 (14.9%) non-ESRD and seven (43.7%) ESRD limbs. Limb salvage was 84.4% and 80.2% in those without and 52.5% and 52.5% in those with ESRD at 1 and 3 years, respectively (p = 0.01). Thirty-day mortality was 2.2%. Overall actuarial survival was 82.2% and 62.1% at 1 and 3 years, respectively, and did not differ significantly between patients with and without ESRD (p = 0.66). Infrapopliteal angioplasty is a safe technique with low procedural morbidity and mortality. However, the inferior wound-healing and limb-salvage rates observed in patients with renal failure bring to question the utility of infrapopliteal angioplasty in this population. Presented at the Fifteenth Annual Winter Meeting of the Peripheral Vascular Surgery Society, Steamboat Springs, CO, January 28-30, 2005.     

Fluorescent substrate assay for antithrombin III.

A sensitive method for the assay of antithrombin III activity is described using a synthetic fluorescent tripeptide, CBZ-gly-pro-arg-4-methoxy-αNA, as a substrate for thrombin. The inhibitor activity in 0.5 μl of plasma (not defibrinated) is determined with assay precision comparable to clotting and immunologic methods. Substrate assay values for normal range samples correlate with immunologic test values while abnormally low inhibitor samples give smaller substrate assay results.     

Recovery Kinetics of Oxygen Uptake Is Abnormally Prolonged in Patients with Mustard/Senning Repair for Transposition of the Great Arteries

The aim of this study was to evaluate the ability to recover from exercise in patients with a Mustard/Senning (M/S) repair for transposition of the great arteries and to identify the major determinants. A total of 40 consecutive patients with a M/S repair at a mean age of 10.0 ± 9.8 months underwent maximal cardiopulmonary exercise testing at 19.5 ± 11.3 years of age. Results were compared to those of a cohort of 153 healthy individuals. Decay of oxygen uptake (VO₂), CO₂ (VCO₂), minute ventilation (VE), heart rate (HR) was calculated for the first minute of recovery. M/S patients had reduced peak VO₂ (22.9 ± 7.2 vs 34.2 ± 9.5 ml O₂/kg/min, p < 0.0001) and VO₂ slope (0.27 ± 0.10 vs 0.47 ± 0.2 L O₂/min, p < 0.0001), Peak O₂ pulse (p < 0.0001) and peak HR (p = 0.001) were reduced. VCO₂ and VE slopes were reduced (p < 0.0001 for both), whereas HR slope was similar (p = 0.38). In M/S patients, the only independent determinants of VO₂ slope during recovery were pulse O₂ slope (p < 0.0001) and VCO₂ slope (p < 0.0001). In M/S patients, a limited cardiopulmonary reserve affects not only maximal exercise responses but also the recovery phase. A prolonged recovery of O₂ pulse and a prolonged CO₂ retention with subsequent prolonged hyperpnea are the main determinants of the delayed recovery.     

Prenatal molecular diagnosis in hypertrophic cardiomyopathy: report of the first case

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disease that may cause premature sudden death, especially in teenagers and young adults. The recent progress in the molecular genetics of the disease has made genetic testing sometimes available in clinical practice. We report the case of a couple who still requested prenatal molecular testing after detailed information had been given through a multidisciplinary consultation. Prenatal diagnosis in HCM is associated with complex medical and psychological implications, in addition to general ethical considerations, as the potential value of the diagnosis is counterbalanced by the highly variable expression of the disease and the difficulty in predicting its evolution. The R403L mutation in the MYH7 gene had been previously identified in this family, characterized by a malignant form of HCM. In the specific context of this case, we decided to agree to the request of the parents and performed the prenatal diagnosis. To the best of our knowledge, this is the first report of a prenatal molecular diagnosis performed in the context of HCM.     

Better surgical prognosis for patients with complete atrioventricular septal defect and Down's syndrome

Background

Several studies have shown that Down's syndrome is not a risk factor for biventricular repair of complete atrioventricular septal defects. However, few data are available about the comprehensive outcome of all the cardiac surgical procedures in patients with trisomy 21, including palliative surgery.

Methods

This is a retrospective study of 206 consecutive patients who underwent cardiac surgery from January 1992 to January 2002. Data about mortality and morbidity were analyzed and the impact of Down's syndrome was evaluated.

Results

Overall mortality was 7.7%. Actuarial survival was 94% among patients with Down's syndrome versus 86% of the group with normal karyotype (p = 0.12). The presence of unbalanced ventricles was the only independent risk factor affecting survival at multivariate analysis (p < 0.0001). The need for a Norwood type surgery was more frequent among non-Down patients (12.0% vs 1.5%, p = 0.02) as was the prevalence of pulmonary artery banding operations (22.9% vs 9.3%, p = 0.04). Cumulative mortality after palliation was higher in non-Down patients (44% vs 2.9%, p = 0.0001). Freedom from reoperation was lower in the group with normal chromosomes in respect to patients with Down's syndrome (81.4% vs 94.6%, p = 0.04), due to the higher prevalence of anomalies of the mitral valve (4.9% vs 1.8%, p = 0.03) or left ventricular outflow tract (7.3% vs 0%, p = 0.01).

Conclusions

Down patients showed a decreased risk for biventricular repair and lower mortality and morbidity in cases of complex cardiac malformations requiring complex palliative operations.     

System to decrease length of stay for vascular surgery

OBJECTIVES: Reduction of length of stay (LOS) is critical for optimal use of hospital resources. We developed and evaluated a system to aggressively reduce LOS for vascular surgery. METHOD: Key to this system, which we introduced on January 1, 2001, was appointment of a LOS officer, who communicated daily during hospitalization with patients and families about discharge planning, organized outpatient services for wound care and rehabilitation to transition patients quickly to nonhospital care, and had biweekly meetings with relevant paramedical services. LOS for 509 patients operated on in 2000 (standard group) was compared with LOS for 474 operated on in 2001 and 595 patients operated on in 2002 (LOS reduction groups). Data for all patients with aortic aneurysm, carotid artery stenosis, lower extremity critical ischemia or amputation, and foot debridement were included. RESULTS: LOS in 2000 averaged 8.5 days, compared with 5.9 days in 2001 and 5.6 days in 2002. All decreases in LOS for each diagnostic category in 2001 and 2002 were statistically significant (P = <.001-.03). There was no significant increase in readmission rate (2.2% vs 1.9% and 2.0%, respectively), mortality rate (0.8% vs 0.6% and 0.7%, respectively), or percent of patients who received endovascular treatment (18% vs 16% and 14%, respectively). These decreases in LOS saved the hospital more than US dollars 616200 in 2001, and US dollars 847550 in 2002 (US dollars 500/patient-day). CONCLUSIONS: A committed LOS officer with major specific daily responsibilities for decreasing LOS and discharging patients resulted in a 31% to 33% decrease in LOS, with important cost savings to the hospital and no negative effect on patient care.