Timothy J. Nypaver

Long-term results of venous reconstruction after vascular trauma in civilian practice

The natural history of venous reconstruction (VR) in terms of patency and clinical outcome after vascular trauma has not been well documented. This study consists of 32 patients who had VR performed for extremity vascular trauma and were available for long-term assessment (mean follow-up time 49 months, range 6 to 108 months). The types of repair performed were as follows: lateral venorrhaphy (simple repair) (56%), interposition grafting (22%), patch repair (12.5%), and end-to-end repair (9.5%). Seventeen patients underwent venography after the operation with documentation of repair patency in eight patients (46%) and thrombosis in nine (54%). Only two patients had significant clinical edema at follow-up examination. Noninvasive venous evaluation consisted of Doppler ultrasonography, impedance plethysmography, photoplethysmography, and color-flow duplex scanning (CFDS). The photoplethysmography-derived venous refilling time of the injured extremity was 34.9 +/- 16.2 seconds whereas that of the contralateral noninjured extremity was 36.8 +/- 16.1 seconds (p = 0.5). Based on standard criteria for CFDS, 90% of VRs were patent. Eight repairs that were patent in the early postoperative period remained patent on CFDS. Of the nine repairs with early thrombosis, eight were assessed as patent on follow-up CFDS. In conclusion, VR is a durable surgical procedure associated with minimal morbidity, good long-term patency, and preservation of venous competence. The natural history of thrombosed VRs appears to be one of thrombus absorption with recanalization.

Surgical complications of transaxillary arteriography: A case-control study

PURPOSEnThe purpose of this study was to review the complications of transaxillary arteriography (TRAX), determine clinical factors associated with their occurrence, and define optimal treatment methods.nnnMETHODSnA retrospective review of 842 consecutive TRAX studies performed in a large, urban, tertiary care, academic medical center was undertaken. Patients with complications were compared with a concurrent randomized control group without complications with the use of a multivariate analysis model. Results of operative therapy for nerve injury were compared with those of nonoperative therapy.nnnRESULTSnNineteen (2.3%) complications were identified including 14 nerve injuries, four expanding hematomas/pseudoaneurysms without neurologic deficit, and one puncture site thrombosis. Several statistically significant or suggestive findings associated with the occurrence of complications were identified: female sex (odds ratio [OR] = 4.7), systolic blood pressure > or = 150 mm Hg at the conclusion of TRAX (OR = 9.5), periprocedural systemic heparin anticoagulation (OR = 7.9), concomitant use of intraarterial thrombolysis or percutaneous angioplasty (OR = 12.0), and duration of procedure > or = 90 minutes (OR = 4.0). Patients who underwent prompt exploration (< or = 4 hours from symptom onset) for nerve injuries were more likely to have complete resolution of their neurologic deficits (five of six patients) than those who were observed or underwent delayed operation (three of eight patients) (OR = 8.3).nnnCONCLUSIONSnAggressive treatment of post-TRAX hypertension, limitation of TRAX duration, delay of postprocedure anticoagulation, and use of alternative sites for arterial puncture in female patients or patients undergoing catheter-based intervention may reduce the incidence of TRAX-related complications. In patients who have neurologic deficits prompt surgical exploration of the puncture site with decompression of the involved nerve(s) may reduce the incidence of prolonged deficits.

Response to angiotensin inhibition in rats with sustained renovascular hypertension correlates with response to removing renal artery stenosis

PURPOSEnSustained (late-phase) renovascular hypertension is associated with lower plasma renin activity than is the early phase. It is not clear to what extent this reduced plasma renin activity reflects diminished influence of the renin-angiotensin system. It also is not clear whether this change in the character of the disease influences the effectiveness of surgical removal of the renal artery stenosis in reversing hypertension. Using an animal model of sustained (> or =10 weeks after renal artery clipping) two-kidney, one-clip renovascular hypertension, we hypothesized that the magnitude of the depressor response to selective angiotensin II receptor blockade with losartan would reflect the influence of the renin-angiotensin system on hypertension and enable us to predict the depressor response to subsequent surgical removal of the clip.nnnMETHODSnThe left renal arteries of 20 male Sprague-Dawley rats weighing 150 to 200 gm were fitted with a silver clip (0.23 mm internal diameter). Systolic blood pressure was measured by means of tail-cuff plethysmography for 10 weeks. Rats were then given losartan orally (30 mg/kg a day) for 1 week while blood pressure was monitored. After an additional week to allow recovery, 13 rats underwent surgical unclipping, and seven underwent sham repair. Blood pressure again was monitored over the final week.nnnRESULTSnAll two-kidney one-clip rats had hypertension 10 weeks after clipping (mean systolic blood pressure 206 +/- 10 mm Hg). Losartan decreased systolic blood pressure by 36 +/- 6 mm Hg. The response was variable, ranging from 3 to 66 mm Hg, and overall blood pressure did not normalize (170 +/- 8 mm Hg). Subsequent surgical unclipping decreased systolic blood pressure by 46 +/- 9 mm Hg. Again the response was variable, ranging from 10 to 99 mm Hg, although overall blood pressure did not normalize (164 +/- 7 mm Hg). The decrease in blood pressure after unclipping showed a high correlation with the blood pressure decrease after losartan administration (r = 0.861, p < 0.001). Resting plasma renin activity (before intervention) was 16 +/- 4 ng angiotensin I per milliliter per hour and was not predictive of the response to either losartan or surgical unclipping. The rats subjected to sham operations had no statistically significant changes in blood pressure. Histologic evaluation showed patent renal arteries without appreciable stenosis or intimal hyperplasia after removal of the clips.nnnCONCLUSIONSnIn sustained two-kidney, one-clip renovascular hypertension, the depressor response to angiotensin II receptor blockade is attenuated, suggesting that late-phase hypertension becomes increasingly angiotensin II-independent. In our model, the extent to which sustained renovascular hypertension becomes refractory to 7 days of angiotensin II blockade is highly predictive of the ultimate outcome of surgical repair of renal artery stenosis.

Aortoscopy: A guidance system for endoluminal aortic surgery

PURPOSEnThe aim of this project was to evaluate the feasibility of aortoscopy for guidance of endoluminal aortic procedures and to determine whether aortoscopy has advantages over fluoroscopy in a pig model.nnnMETHODSnTo establish feasibility aortoscopic guidance was used for making endoluminal aortic measurements, cannulating small arteries for arteriograpy, and placing intraaortic stents and grafts in 11 pigs. To compare aortoscopy and fluoroscopy measurements were made and stents were placed by a surgeon using only aortoscopic guidance in 10 pigs and by an interventional radiologist using only fluoroscopic guidance in 10 pigs. Postmortem dissections were performed to determine measurement and device placement accuracy.nnnRESULTSnIn the feasibility study aortoscopic measurements differed from postmortem measurements by a mean distance (+/- SD) of 1.2 +/- 0.2 mm. Stents and grafts were placed a mean of 2.3 +/- 1.9 mm distal to the most inferior renal artery with no stent covering an orifice. All attempts at cannulating spinal arteries greater than 2 mm in diameter were successful. In the comparison of aortoscopic and fluoroscopic guidance, fluoroscopic measurements differed from postmortem measurements by 2.6 +/- 2.4 mm (p = 0.223). Stents placed with aortoscopic guidance were 1.1 +/- 1.3 mm distal to the most inferior renal artery, whereas stents placed with fluoroscopic guidance were 3.4 +/- 2.5 mm distal to the most inferior renal artery (p = 0.019).nnnCONCLUSIONSnThese results demonstrate that aortoscopy is a useful guidance system for endoluminal aortic procedures and may have advantages over fluoroscopy alone.

Critical Limb Ischemia in Patients with End-Stage Renal Disease: Do Long-Term Results Justify An Aggressive Surgical Approach?

End-stage renal disease (ESRD) patients probably represent the most difficult group of patients vascular surgeons are called upon to treat for critical limb ischemia. Advanced lower extremity arterial occlusive disease and frequent comorbidities make infrainguinal arterial bypass grafting (IABG) in this population both technically and medically challenging. Results of IABG are far inferior to those in non-ESRD patients. The greatest limitation to limb salvage appears to be progressive tissue necrosis and infection despite a patent bypass graft, a problem nearly unique to ESRD. Clinical predictors of outcome for IABG in this population have not been well established. The site and extent of tissue loss, the presence of associated infection, and the degree of pedal level occlusive disease have been identified as potentially important predictors. Improving outcome for ESRD patients with critical limb ischemia requires the establishment of firm guidelines for IABG to avoid futile and risky attempts at bypass i...

PC180. Superficial Femoral Artery Balloon Angioplasty Stent Implantation-Outcome Stratified by Type of Follow-up Evaluation: Arterial Duplex Imaging versus Ankle-Brachial Index Only

Results: Clinical case 2 describes a 48-year-old woman with a history of Takayasus arteritis, prior proximal descending thoracic aorta to infrarenal abdominal aortic bypass and bypass to the left renal artery for mid-aortic syndrome, and atrophic right kidney presented with severe hypertension, fluid overload, and hyperkalemia, and a creatinine of 5.8 mg/dL requiring urgent dialysis. She was anuric and dialysis dependent. Magnetic resonance angiography revealed occlusion of the left renal artery bypass which originated from the aortic bypass graft and collateral filling of the left kidney with differential areas of perfusion (Fig 2). She underwent redo aortic graft to left renal artery bypass 18 days after her initial presentation. Upon discharge, she was no longer dialysis dependent and her creatinine has normalized. Conclusions: Two patients presenting with dialysis dependent acute renal failure underwent delayed renal artery revascularization, greater than 14 days from their presentation. Complete renal recovery with return to baseline renal function was observed in these patients. In select patients, delayed renal artery revascularization (>48 hours of warm ischemic time) is controversial, but can be associated with complete renal recovery and freedom from dialysis.

Benefit of Arterial Duplex Ultrasound Stent Imaging After Superficial Femoral Artery Stent Implantation: Impact of Surveillance Method on Postprocedural Outcome

Objective: In-stent stenosis is a frequent complication of superficial femoral artery (SFA) endovascular intervention and can lead to stent occlusion or symptom recurrence. Arterial duplex ultrasound stent imaging (ADSI) can be used in the surveillance for recurrent stenosis; however, its uniform application is controversial. In this study, we aimed to determine, in patients undergoing SFA stent implantation (SI), whether surveillance with ADSI yielded a better outcome than in those with only anklebrachial index (ABI) follow-up. Methods: We performed a retrospective analysis of all patients undergoing SFA SI for occlusive disease at a tertiary care referral center between 2009 and 2016. The patients were divided into those with ADSI (ADSI group) and those with ABI follow-up only (ABI group). Life-table analysis comparing stent patency, major adverse limb event (MALE), limb salvage, and mortality between groups was performed. Results: There were 248 patients with SFA SI included, 160 in the ADSI group and 88 in the ABI group. Groups were homogeneous regarding clinical indication (claudication/critical limb ischemia, ADSI 39%/61% vs ABI 38%/62%; P 1⁄4 .982) and TransAtlantic Inter-Society Consensus classification (A/B/C/D for ADSI 17%/45%/16%/22% and ABI 21%/43%/16%/20%; P 1⁄4 .874). Primary patency (PP) was similar between groups at 12, 36, and 56 months (ADSI, 65%/43%/32%; ABI, 69%/34%/34%; P 1⁄4 .770), whereas ADSI patients showed an improved assisted PP (84%/68%/54%) vs ABI (76%/38%/38%; P 1⁄4 .008) and secondary patency (Fig 1). There was a greater freedom from MALE in the ADSI group (91%/76%/64%) vs the ABI group (79%/46%/46%; P < .001) at 12, 36, and 56 months of followup. ADSI patients were more likely to undergo an endovascular procedure as their initial post-SFA SI intervention (P 1⁄4 .001), whereas ABI patients were more likely to undergo an amputation (P < .001; Fig 2). Conclusions: In SFA SI, patients with ADSI follow-up demonstrate an advantage in assisted PP and secondary patency and are more likely to undergo an endovascular reintervention. These factors likely effected a

Contrast-induced nephropathy after peripheral vascular intervention: Long-term renal outcome and risk factors for progressive renal dysfunction

Objective Contrast‐induced nephropathy (CIN) is a frequently used quality outcome marker after peripheral vascular interventions (PVIs). Whereas the factors associated with CIN development have been well documented, the long‐term renal effects of CIN after PVI are unknown. This study was undertaken to investigate the long‐term (1‐year) renal consequences of CIN after PVI and to identify factors associated with renal function deterioration at 1‐year follow‐up. Methods From 2008 to 2015, patients who had PVI at our institution (who were part of a statewide Vascular Interventions Collaborative) were queried for those who developed CIN. CIN was defined by the Collaborative as an increase in serum creatinine concentration of at least 0.5 mg/dL within 30 days after intervention. Preprocedural dialysis patients or patients without postprocedural creatinine values were excluded. Preprocedural, postprocedural, and 1‐year serum creatinine values were abstracted and used to estimate glomerular filtration rate (GFR). &Dgr;GFR was defined as preprocedural GFR minus 1‐year GFR. Univariate and multivariate analyses for &Dgr;GFR were performed to determine factors associated with renal deterioration at 1 year. Results From 2008 to 2015, there were 1323 PVIs performed; 881 patients met the inclusion criteria. Of these, 57 (6.5%) developed CIN; 47% were male, and 51% had baseline chronic kidney disease. CIN resolved by discharge in 30 patients (53%). Using multivariate linear regression, male sex (P = .027) and congestive heart failure (P = .048) were associated with 1‐year GFR decline. Periprocedural variables related to 1‐year GFR decline included percentage increase in 30‐day postprocedural creatinine concentration (P = .025), whereas CIN resolution by discharge (mean, 13.1 days) was protective for renal function at 1 year (P = .02). A post hoc analysis was performed with 50 PVI patients (randomly selected) who did not develop CIN, comparing their late renal function with that of the CIN group stratified by the periprocedural 30‐day variables. Patients with CIN resolution at discharge had similar 1‐year renal outcomes to non‐CIN patients, whereas the CIN‐persistent (at discharge) patients had greater renal deterioration at 1 year compared with non‐CIN patients (P = .016). Conclusions Male sex and congestive heart failure are risk factors for further renal function decline in patients developing CIN after PVI. The magnitude and duration of increase in creatinine concentration (CIN persistence at discharge) correlated with late progressive renal dysfunction in CIN patients, suggesting that early‐resolving CIN is relatively benign.

Creating accountable care for carotid angioplasty and stenting: A multidisciplinary carotid revascularization board.

Background: We tested the feasibility of a mandated multidisciplinary carotid revascularization board (MDCB) to review, approve and monitor all carotid artery and stenting (CAS) procedures and outcomes at our institution. Methods: The board was composed of vascular surgeons, cardiologists, interventional neuroradiologists, neurosurgeons, and neurologists, who met weekly to facilitate an evidence-based, consensus recommendation to ensure appropriate CAS referral. Results: The board successfully reviewed and continues to review and approve all CAS procedures at our center. Of the 69 patients considered high risk for standard surgical treatment, 42 patients were symptomatic and 27 patients were asymptomatic. Their mean age was 70.5-year-old and the median degree of stenosis was 79%. In the 74 procedures, periprocedural complications occurred at the following rates: 2.7% death, 2.7% major stroke, 2.7% minor stroke, and 2.7% myocardial infarction (MI) within 30 days of the procedure. At 1 year the primary endpoints of ipsilateral stroke and neurovascular-related death were observed in 8.1% and 2.7% of the patients, respectively. At mean follow-up of 21 months, 18.8% of the patients (13/69) had died (including all causes), and 14.5% (10/69) experienced stroke (including nontarget strokes). Target vessel revascularization was needed in 2.9% patients. Conclusions: A mandated multidisciplinary carotid revascularization board MDCB is feasible and potentially advantageous in real clinical practice. It establishes a model for accountable care by providing a mechanism for institutional oversight, credentialing operators, quality review, standardizing care, cost containment and eliminating the “subspecialty silo mentality.”