Predictors of intervention and mortality in patients with uncomplicated acute type B aortic dissection.

OBJECTIVE: Patients with uncomplicated acute type B aortic dissection (uATBAD) have historically been managed with medical therapy. Recent studies suggest that high-risk patients with uATBAD may benefit from thoracic endovascular aortic repair. This study aims to determine the predictors of intervention and mortality in patients with uATBAD. METHODS: All patients admitted with uATBAD from 2000 to 2014 were reviewed, and those with computed tomographic angiography imaging were included. Multiplanar reconstruction was used to obtain double orthogonal oblique measurements. All measurements were obtained by a specialized cardiovascular radiologist (D.O.). The maximum aortic diameter, proximal descending thoracic aorta false lumen (FL) diameter, and area were recorded. Outcomes, including the need for intervention and mortality, were tracked over time. Data were analyzed by stratified Kaplan-Meier and multiple Cox regression analysis using SAS v 9.4 (SAS Institute, Cary, NC). RESULTS: During the study period, 294 patients with uATBAD were admitted with 156 having admission computed tomographic angiography imaging available for analysis. The cohort had an average age of 60.6 years (±13.6 years); 60% were males. The average follow-up time was 3.7 years (interquartile range, 2.1-6.9). A stratified analysis demonstrated the most sensitive cutoff for mortality was aortic diameter >44 mm (P < .01), and it appeared to be a threshold effect with minimal additional information added by finer size stratification. FL diameter did not predict mortality in our series (P = .36). Intervention-free survival, alternatively, appeared to decrease over the range of diameters from 35 to 44 mm (P < .01). An FL diameter >22 mm was associated with decreased intervention-free survival (P < .04). Age >60 years on admission also demonstrated decreased survival compared with those ≤60 years of age (P < .01). Diameter >44 mm persisted as a risk factor for mortality (hazard ratio, 8.6; P < .01) after adjustment for diabetes (6.7; P < .01), age (1.06/y; P < .01), history of stroke (5.4; P < .01), connective tissue disorder (2.3; P < .01), and syncope on admission (9.5; P < .04). The 1-, 5-, and 10-year intervention rate for patients with admission aortic diameter >44 mm was 18.8%, 29.5%, and 50.3%, respectively, compared with 4.8%, 13.3%, and 13.3% in the ≤44 mm group (P < .01). CONCLUSIONS: Aortic diameter >44 mm is a predictor of mortality after adjustment for other significant risk factors. Age >60 years on admission is a predictor of mortality. An FL diameter >22 mm as well as those with maximum aortic diameter >44 mm on admission were associated with decreased intervention-free survival. Patients with these high-risk criteria may benefit from thoracic endovascular aortic repair. Further studies are needed to further define those patients at highest risk and, thus, most likely to benefit from early intervention.

Need for Limb Revascularization in Patients with Acute Aortic Dissection is Associated with Mesenteric Ischemia.

BACKGROUND: Acute aortic dissection (AAD) can cause limb ischemia due to branch vessel occlusion. A minority of patients have persistent ischemia after central aortic repair and require peripheral arterial revascularization. We investigated whether the need for limb revascularization is associated with adverse outcomes. METHODS: We reviewed our cases of AAD from 2000 to 2014 and identified patients with malperfusion syndromes (coronary, cerebral, spinal, visceral, renal, or peripheral ischemia). Patients with DeBakey I/II (Stanford type A) dissection had urgent open repair of the ascending aorta. Patients with DeBakey III (Stanford type B) dissection were initiated on anti-impulse medical therapy and had either open aortic repair or thoracic endovascular aortic repair for malperfusion syndromes. Patients with persistent lower limb ischemia after aortic repair usually had either extra-anatomic bypass grafting or iliac stenting. Some DeBakey III patients had peripheral revascularization without central aortic repair. We performed univariate and multivariate analysis to determine the effects of need for limb revascularization and clinical outcomes. RESULTS: We treated 1,015 AAD patients (501 [49.4%] DeBakey I/II and 514 [50.6%] DeBakey III) with a mean age of 59.7 ± 14.5 years (67.5% males). Aortic repair was performed in all DeBakey I/II patients and in 103 (20.0%) DeBakey III patients. Overall 30-day mortality was 11.3%. Lower limb ischemia was present in 104 (10.3%) patients and was more common in DeBakey I/II compared with DeBakey III dissections (65.4% vs. 34.6%; odds ratio [OR] 2.1, confidence interval [CI] 1.4-3.2; P = 0.001). Among the 40 patients who required limb revascularization, there was no difference in need for revascularization between DeBakey I/II and III patients. Patients requiring limb revascularization were more likely to have mesenteric ischemia compared with the rest of the cohort in both DeBakey I/II (P = 0.037) and DeBakey III dissections (P < 0.001) with worse 10-year survival (21.9 % vs. 59.2%, P < 0.001). When adjusted for other malperfusion syndromes, patients with limb revascularization had similar long-term survival compared to uncomplicated dissection patients (P = 0.960). CONCLUSIONS: Patients requiring lower limb revascularization after treatment for AAD are more likely to have mesenteric ischemia and worse survival. The need for limb revascularization is a marker for more extensive dissection and should prompt evaluation for visceral malperfusion.

Aneurysmal degeneration of the thoracoabdominal aorta after medical management of type B aortic dissections.

BACKGROUND: Patients with uncomplicated type B aortic dissections who are managed medically are at risk of aortic aneurysmal degeneration over time. However, the effect of improvement in antihypertensive medications and stricter blood pressure control is unknown. The goal of this study was to determine the rate of aneurysmal degeneration in a contemporary cohort of patients with medically treated type B dissection. METHODS: Included were all patients with acute uncomplicated type B aortic dissection who were initially managed medically between March 1999 and March 2011 and had follow-up axial imaging studies. Maximum aortic growth was calculated by comparing the initial imaging study to the most current scan or imaging obtained just before any aortic-related intervention. An increase of ≥5 mm was the threshold considered as aortic growth. Predictors of aortic aneurysmal degeneration were determined using Cox proportional hazards models. RESULTS: We identified 200 patients (61% men) with medically managed acute type B dissections receiving multiple imaging studies. Patients were an average age of 63.4 years, and 75.5% had a history of hypertension. Mean follow-up was 5.3 years (range, 0.1-14.7 years). Mean time between the initial and final imaging studies was 3.2 years (range, 0.1-12.9 years). At 5 years, only 51% were free from aortic growth. Fifty-six patients (28%) required operative intervention (50 open, 6 endovascular repair) for aneurysmal degeneration, and the actuarial 5-year freedom from intervention was 76%. After excluding five patients (2.5%) with early rapid degeneration requiring intervention within the first 2 weeks, the mean rate of aortic growth was 12.3 mm/y for the total aortic diameter, 3.8 mm/y for the true lumen diameter, and 8.6 mm/y for the false lumen diameter. Only aortic diameter at index presentation >3.5 cm was a risk factor for future growth (odds ratio, 2.54; 95% confidence interval, 1.34-4.81; P < .01). Complete thrombosis of the false lumen was protective against growth (odds ratio, 0.19; 95% confidence interval, 0.11-0.42; P < .01). CONCLUSIONS: Although medical management of uncomplicated acute, type B aortic dissections has been the standard of care, at 5 years, a significant number of patients will require operative intervention for aneurysmal degeneration. Further studies of early intervention (eg, thoracic endovascular aortic repair) for type B aortic dissection to prevent late aneurysm formation are needed.

The natural history of medically managed acute type B aortic dissection.

OBJECTIVE: Although medical management of acute uncomplicated type B aortic dissection remains the standard of care, contemporary data regarding the natural history of medically treated patients are sparse. The goal of this study was to evaluate the natural history of patients with acute type B aortic dissection who were initially managed with medical therapy alone. METHODS: All patients with acute type B aortic dissection who were initially managed medically between March 1999 and March 2011 were included. Failure of medical therapy was defined as any death or aorta-related intervention. Early failure occurred within 15 days of presentation. Predictors of long-term outcomes were determined using backward stepwise regression. RESULTS: A total of 298 patients with medically managed acute type B dissections were identified. The cohort had an average age of 65.9 years at presentation and was 61.7% male. There were 174 (58.4%) failures including 119 deaths and 87 interventions (24 endovascular, 63 open); 57 (66%) interventions were performed for aneurysmal degeneration. There were 37 (12%) early failures including 14 deaths and 25 interventions (10 endovascular, 15 open). Aneurysmal degeneration was the indication for intervention in six patients (24%). Mean follow-up was 4.2 years (range, 0.1-14.7 years). Kaplan-Meier estimate demonstrated that freedom from intervention was 77.3% ± 2.4% at 3 years and 74.2% ± 2.5% at 6 years. There were no predictors of freedom from intervention. Kaplan-Meier estimate demonstrated that the intervention-free survival was 55.0% ± 3.0% at 3 years and 41.0% ± 3.2% at 6 years. End-stage renal disease was predictive of failure of medical treatment (hazard ratio, 2.60; confidence interval, 1.19-5.66; P = .02), and age >70 years was protective against failure (hazard ratio, 0.97; confidence interval, 0.95-0.98; P < .01). Kaplan-Meier estimate demonstrated that survival after 6 years was higher in patients who underwent interventions (76% vs 58%; P = .018). CONCLUSIONS: The majority of patients with acute type B dissection will fail medical therapy over time as evidenced by a 6-year intervention-free survival of 41%. Patients who underwent any aortic intervention had a significant survival advantage over those who were treated with medical management alone. Further study is necessary to determine who will benefit most from early intervention.

Role of statin therapy and angiotensin blockade in patients with asymptomatic moderate carotid artery stenosis.

BACKGROUND: The purpose of this study was to evaluate the 10-year outcome of patients presenting with asymptomatic moderate carotid artery stenosis, and to determine which factors correlate with progression of disease to stroke or revascularization. METHODS: A retrospective review of all new patients presenting with asymptomatic moderate carotid artery stenosis from July 1998 to December 2001 was undertaken. Patients were consecutively identified and included by using duplex ultrasonography to identify moderate carotid disease. Variables were recorded for all patient encounters through June 2010. The primary end point was occurrence of ipsilateral cerebrovascular stroke or revascularization event (SORE). Statin therapy and angiotensin blockade (STAB) were categorized as follows: STAB(0)-medical treatment with neither statin therapy nor angiotensin blockade, STAB(1)-treatment with only one of the two, STAB(2)-treatment with both. An amortized cost model analyzed the cost of SORE-free survival. RESULTS: Over a 42-month period, 468 carotids in 366 patients with an average age of 69.0 ± 8.7 years were evaluated. Over a mean follow-up of 6.6 ± 2.7 years, SORE occurred in 150 (32.1%) carotid arteries. Hyperlipidemia was predictive of SORE (hazard ratio [HR]: 1.543, 95% confidence interval [CI]: 1.053-2.262, P = 0.03). Medical therapies protective against SORE were beta-blockade (HR: 0.612, 95% CI: 0.435-0.861, P < 0.05), STAB(1) (HR: 0.487, 95% CI: 0.336-0.706, P < 0.01), and STAB(2) (HR: 0.149, 95% CI: 0.089-0.248, P < 0.01). At 10 years, SORE-free survival in STAB(2) was 82.7% ± 4.6%, STAB(1) was 56.3% ± 5.0%, and STAB(0) was 29.3% ± 5.4% (P < 0.01). The cost per SORE-free year in STAB(2) was $1,695.40 ± $275.60, STAB(1) was $3,916.80 ± $605.44, and STAB(0) was $4,126.40 ± $427.23 (P < 0.01). CONCLUSION: These data demonstrate the clinical and financial advantage of using both statin therapy and angiotensin pathway blockage in patients with asymptomatic moderate carotid artery stenosis.

Impact of operative indication and surgical complexity on outcomes after thoracic endovascular aortic repair at National Surgical Quality Improvement Program Centers.

INTRODUCTION: Thoracic endovascular aortic repair (TEVAR) devices are increasingly being utilized to treat aortic pathologies outside of the original Food & Drug Administration (FDA) approval for nonruptured descending thoracic aorta aneurysms (DTAs). The objective of this study was to evaluate the outcomes of patients undergoing TEVAR, elucidating the role of surgical and pathologic variables on morbidity and mortality. METHODS: National Surgical Quality Improvement Program (NSQIP) data were reviewed for all patients undergoing endovascular thoracic aorta repair from 2005 to 2007. The patients' operative indication and surgical complexity were used to divide them into study and control populations. Comorbid profiles were assessed utilizing a modified Charlson Comorbidity Index (CCI). Thirty-day occurrences of mortality and serious adverse events (SAEs) were used as study endpoints. Univariate and multivariate models were created using demographic and clinical variables to assess for significant differences in endpoints (P ≤ .05). RESULTS: A total of 440 patients undergoing TEVAR were identified. When evaluating patients based on operative indication, the ruptured population had increased mortality and SAE rates compared to the nonruptured DTA population (22.6% vs 6.2%;P < .01 and 35.5% vs 9.1%;P < .01, respectively). Further analysis by surgical complexity revealed increased mortality and SAE rates when comparing the brachiocephalic aortic debranching population to the noncovered left subclavian artery population (23.1% vs 6.5%; P = .02 and 30.8% vs 9.1%; P < .01, respectively). Multivariate analysis demonstrated that operative indication was not a correlate of mortality or SAEs (odds ratio [OR], 0.95; P = .92 and OR, 1.42; P = .39, respectively); however, brachiocephalic aortic debranching exhibited a deleterious effect on mortality (OR, 8.75; P < .01) and SAE rate (OR, 6.67; P = .01). CONCLUSION: The operative indication for a TEVAR procedure was not found to be a predictor of poor patient outcome. Surgical complexity, specifically the need for brachiocephalic aortic debranching and aortoiliac conduit, was shown to influence the occurrence of SAEs in a multivariate model. Comparative data, such as these, illustrate real-world outcomes of patients undergoing TEVAR outside of the original FDA-approved indications. This information is of paramount importance to various stakeholders, including third-party payers, the device industry, regulatory agencies, surgeons, and their patients.

Single-incision laparoscopic cholecystectomy: a cost comparison.

BACKGROUND: Single-incision laparoscopic cholecystectomy (SILC) should not cost more or less than traditional laparoscopic cholecystectomy (LC). METHODS: Retrospective cost data were collected from the accounting records of a single institution. A direct comparison of LC and SILC was conducted. Data on the SILC cases converted to LC were included. The total operating room (OR) cost (actual cost to the hospital for equipment, time, and personnel) and the total OR charges (total derived from the OR cost plus a margin to cover overhead costs beyond material costs) were examined. The total hospital charges (OR charges plus hospital charges accrued in the perioperative period) also were included. Descriptive statistics were used to analyze the data, with p values less than 0.05 considered statistically significant. RESULTS: Over a period of 19 months, 116 cases of minimally invasive cholecystectomy were evaluated. Of the 116 patients, 48 underwent LC during the first half of that period, and 68 patients underwent SILC during the second half of that period. Nine of the single-incision procedures were converted to traditional LC, for a 13% conversion rate. The groups were well matched from a demographics standpoint, with no significant differences in age, gender, body mass index (BMI), diagnoses, American Society of Anesthesiology (ASA) class, or payment. Comparison of all attempted SILCs, including those converted, with all LCs showed no significant difference in cost category totals. A significant difference among all cost variables was found when SILCs were compared with SILCs that required conversion to LC. A significant difference among the cost variables also was found when LCs were compared with converted SILCs. CONCLUSION: The cost for SILC did not differ significantly from that for LC when standard materials were used and the duration of the procedure was considered. Converted cases were significantly more expensive than completed SILC and LC cases.

The impact of socioeconomic factors on outcome and hospital costs associated with femoropopliteal revascularization.

INTRODUCTION: Within the context of healthcare system reform, the cost efficacy of lower extremity revascularization remains a timely topic. The impact of an individual patient's socioeconomic status represents an under-studied aspect of vascular care, especially with respect to longitudinal costs and outcomes. The purpose of this study is to examine the relationship between socioeconomic status and clinical outcomes as well as inpatient hospital costs. METHODS: A retrospective femoropopliteal revascularization database, which included socioeconomic factors (household income, education level, and payor status), in addition to standard demographic, clinical, anatomical, and procedural variables were analyzed over a 3-year period. Patients were stratified by income level (low income [LI] <200% federal poverty level [$42,400 for a household of 4], and higher income [HI] >200% federal poverty level) and revascularization technique (open vs endovascular) and analyzed for the endpoints of primary assisted patency, amortized cost-per-day of patency, and limb salvage. Data were analyzed with univariate and multivariate techniques. RESULTS: A total of 187 cases were identified with complete data for analysis, 146 in the LI and 41 in the HI cohorts. LI patients differed from HI patients by mean age (66.2 +/- 1.0 vs 61.8 +/- 1.5 years, P = .04), high school graduate rate (51.4% vs 85.4%, P < .001), presence of tissue loss (30.1% vs 14.6%, P = .05), female gender (43.7% vs 22.0%, P = .01) and preoperative statin use (45.8% vs 75.6%, P < .001). There were no differences with respect to other comorbidities including smoking status, presence of diabetes, renal insufficiency, anatomic factors or treatment modality (open vs endovascular). Ninety-seven patients underwent endovascular revascularization. The following outcomes were noted in the endovascular subset of LI and HI patients respectively: primary assisted patency (66% vs 71%, P = NS) and 12-month cost-per-day of patency ($166.30 +/- 77.40 vs $22.45 +/- 12.45, P = .05). Ninety-eight patients underwent open revascularization, with the following outcomes in LI and HI patients respectively: primary assisted patency (78% vs 86%, P = NS) and 12-month cost-per-day of patency ($319.43 +/- 225.44 vs $40.47 +/- 4.63, P = .07). Of the 77 patients with critical limb ischemia, 19 underwent eventual amputation. Multivariate analysis demonstrated that income above 100% of the federal poverty line was protective against limb loss (odds ratio 0.06, 95% confidence interval 0.01-0.51, P < .001). CONCLUSION: Income level correlates with advanced presentation, advanced age, and lack of statin use. Although primary assisted patency rate is not affected by income status, an increased cost-per-day of patency and inferior limb salvage is found in lower income patients.

A contemporary rural trauma center experience in blunt traumatic aortic injury.

INTRODUCTION: Traumatic aortic injury (TAI) is a rare yet highly lethal injury associated with blunt force deceleration injury. The adoption of thoracic endovascular aortic repair (TEVAR) has become a safer option than traditional open repair. The purpose of this study is to review a rural trauma center experience with TAI. METHODS: A retrospective analysis was performed, reviewing all patients who presented with TAI between 2000 and 2009. Clinical, anatomical, and procedural variables of all cases were systematically reviewed. Clinical endpoints included mortality, and aortic-related mortality, and hospital length of stay. The study population was stratified by those that underwent surgical repair (SR) and those managed medically (MM). RESULTS: Fifty-six patients presented with blunt TAI; 35 patients (62.5%) were surgically repaired (22 open, 13 TEVAR), while 21 (37.5%) were MM. The only difference in comorbidities was a higher rate of coronary artery disease in MM. Mean hospital arrival time (SR, 188.6 ± 30.3 minutes, MM, 253 ± 65.3 minutes), aortic injury grade (SR, 2.7 ± 0.1; MM, 2.3 ± 0.2), and injury severity score were not significantly different between the groups. Head Abbreviated Injury Score (AIS) was worse in the MM group, while chest AIS was worse in the SR group (P < .05). There were nine (42.9%) deaths in the MM group, while there were only two (5.7%) in the SR group (P < .001). There was no significant difference in aortic-related mortality. Mean follow-up time was not statistically different. CONCLUSION: These data provide a group of stable patients to examine the management of TAI in the endovascular era. The low aortic-related mortality in the MM group demonstrates that there is time for a thorough evaluation in patients sustaining TAI who arrive without hemodynamic instability.

Correlation of cerebral oximetry with internal carotid artery stump pressures in carotid endarterectomy.

OBJECTIVE: This study compares internal carotid artery (ICA) mean stump pressures (SPs) with cerebral oximetry monitoring during carotid endarterectomy (CEA). METHODS: A total of 104 consecutive patients undergoing CEA under general anesthesia (GA) during a 10-month period were prospectively evaluated. Baseline and postcarotid clamp regional cerebral oxygen saturation (rSO(2)) and mean ICA SPs were measured. Demographic, surgical, and medical variables were recorded for each case. RESULTS: There were no postoperative strokes. Thirteen patients were excluded because of incomplete data. Of the 40 patients who had <10% drop in rSO(2), 6 had SP <40 mm Hg. Regional cerebral oxygen saturation with a 15% saturation drop threshold was 76.3% sensitive and 81.1% specific in detecting patients with SP <40 mm Hg. With a threshold of 20% drop, sensitivity and specificity were 57.9% and 86.8%, respectively. CONCLUSIONS: Relative drop in rSO( 2) is neither sensitive nor specific in detecting patients with mean SP <40 mm Hg. These data do not support the use of cerebral oximetry as the sole monitoring modality during carotid endarterectomy under GA.

Impact of hypothermia (below 36 degrees C) in the rural trauma patient.

BACKGROUND: Hypothermia is an independent predictor of mortality based on urban studies. But this association has not been described in the rural setting. This study's purpose was to evaluate hypothermia as a cofactor to mortality, complications, and hospital length of stay (LOS) parameters in the rural trauma setting. STUDY DESIGN: The National Trauma Registry of the American College of Surgeons database for our rural, Level I trauma center was queried for a 5-year period (July 2002 to June 2007) to identify adult trauma patients. Multivariate regression models were used to evaluate the association of hypothermia with mortality; infectious complications; organ dysfunction; and, among survivors, hospital LOS parameters. RESULTS: Of 9,482 adult patients admitted, 1,490 (15.7%) patients were hypothermic. Hypothermia had an adjusted odds ratio of 1.70 for mortality (95% CI, 1.35 to 2.12; p < 0.001). After controlling for covariates, hypothermia was not significantly associated with infectious complications or organ dysfunction, except for arrhythmia (adjusted odds ratio, 1.40; CI, 1.03 to 1.90; p = 0.031). Hypothermia was not associated with a difference in ICU (p = 0.310) or ventilator (p = 0.144) LOS. But a slight increase in hospital days was noted in the hypothermic patient (hazards ratio, 0.890 for discharge; 95% CI, 0.838 to 0.946; p < 0.001). CONCLUSIONS: Hypothermia is a common problem at admission in a rural trauma center. It is associated with an increase in hospitalized days but not with increased ICU or ventilator days among survivors. Other than arrhythmias, it was not significantly associated with other National Trauma Registry of the American College of Surgeons infectious or organ dysfunction complications. Hypothermia is an independent risk factor for mortality in the rural trauma patient.