G. Chad Hughes

Transcatheter aortic-valve replacement with a self-expanding prosthesis.

BACKGROUND We compared transcatheter aortic-valve replacement (TAVR), using a self-expanding transcatheter aortic-valve bioprosthesis, with surgical aortic-valve replacement in patients with severe aortic stenosis and an increased risk of death during surgery. METHODS We recruited patients with severe aortic stenosis who were at increased surgical risk as determined by the heart team at each study center. Risk assessment included the Society of Thoracic Surgeons Predictor Risk of Mortality estimate and consideration of other key risk factors. Eligible patients were randomly assigned in a 1:1 ratio to TAVR with the self-expanding transcatheter valve (TAVR group) or to surgical aortic-valve replacement (surgical group). The primary end point was the rate of death from any cause at 1 year, evaluated with the use of both noninferiority and superiority testing. RESULTS A total of 795 patients underwent randomization at 45 centers in the United States. In the as-treated analysis, the rate of death from any cause at 1 year was significantly lower in the TAVR group than in the surgical group (14.2% vs. 19.1%), with an absolute reduction in risk of 4.9 percentage points (upper boundary of the 95% confidence interval, -0.4; P<0.001 for noninferiority; P = 0.04 for superiority). The results were similar in the intention-to-treat analysis. In a hierarchical testing procedure, TAVR was noninferior with respect to echocardiographic indexes of valve stenosis, functional status, and quality of life. Exploratory analyses suggested a reduction in the rate of major adverse cardiovascular and cerebrovascular events and no increase in the risk of stroke. CONCLUSIONS In patients with severe aortic stenosis who are at increased surgical risk, TAVR with a self-expanding transcatheter aortic-valve bioprosthesis was associated with a significantly higher rate of survival at 1 year than surgical aortic-valve replacement. (Funded by Medtronic; U.S. CoreValve High Risk Study ClinicalTrials.gov number, NCT01240902.).

Transcatheter aortic valve replacement using a self-expanding bioprosthesis in patients with severe aortic stenosis at extreme risk for surgery

OBJECTIVES This study sought to evaluate the safety and efficacy of the CoreValve transcatheter heart valve (THV) for the treatment of severe aortic stenosis in patients at extreme risk for surgery. BACKGROUND Untreated severe aortic stenosis is a progressive disease with a poor prognosis. Transcatheter aortic valve replacement (TAVR) with a self-expanding bioprosthesis is a potentially effective therapy. METHODS We performed a prospective, multicenter, nonrandomized investigation evaluating the safety and efficacy of self-expanding TAVR in patients with symptomatic severe aortic stenosis with prohibitive risks for surgery. The primary endpoint was a composite of all-cause mortality or major stroke at 12 months, which was compared with a pre-specified objective performance goal (OPG). RESULTS A total of 41 sites in the United States recruited 506 patients, of whom 489 underwent attempted treatment with the CoreValve THV. The rate of all-cause mortality or major stroke at 12 months was 26.0% (upper 2-sided 95% confidence bound: 29.9%) versus 43.0% with the OPG (p < 0.0001). Individual 30-day and 12-month events included all-cause mortality (8.4% and 24.3%, respectively) and major stroke (2.3% and 4.3%, respectively). Procedural events at 30 days included life-threatening/disabling bleeding (12.7%), major vascular complications (8.2%), and need for permanent pacemaker placement (21.6%). The frequency of moderate or severe paravalvular aortic regurgitation was lower 12 months after self-expanding TAVR (4.2%) than at discharge (10.7%; p = 0.004 for paired analysis). CONCLUSIONS TAVR with a self-expanding bioprosthesis was safe and effective in patients with symptomatic severe aortic stenosis at prohibitive risk for surgical valve replacement. (Safety and Efficacy Study of the Medtronic CoreValve System in the Treatment of Symptomatic Severe Aortic Stenosis in High Risk and Very High Risk Subjects Who Need Aortic Valve Replacement; NCT01240902).

Midterm Results for Endovascular Repair of Complicated Acute and Chronic Type B Aortic Dissection

BACKGROUND Thoracic endovascular aortic repair (TEVAR) for the management of type B aortic dissections has become more commonplace despite some controversy. Results of endovascular management of complicated acute (<2 weeks from symptom onset) and chronic (>2 weeks) type B aortic dissection with a view towards determining safety, efficacy, and requirement for secondary procedures are reviewed. METHODS Between June 2005 and November 2008, 55 patients (41 men) with a mean age of 59 +/- 12 years (range, 31 to 77 years) underwent TEVAR for the management of complicated acute (n = 22) or chronic (n = 33) type B dissection. Indications in acute dissection included impending or frank rupture in 11 and malperfusion syndromes in 11; the indication in chronic dissections was aneurysmal degeneration in 33. RESULTS Primary technical success was 100%. In-hospital and 30-day rates of death, stroke, and permanent paraplegia/paresis were 2% (n = 1), 0%, and 2% (n = 1), respectively. Median follow-up was 7.1 months (range, 1 to 38 months). Overall actuarial midterm survival was 63% at 38 months, with an aorta-specific actuarial survival of 94%. Two patients (4%) required late conversion to open repair. Postoperative type I or III endoleak occurred in 3 (6%) and type II endoleak in 7 (15%). Two patients underwent subsequent endovascular occlusion. The composite reintervention rate in follow-up was 23.4% (n = 13). CONCLUSIONS Endovascular repair for complicated acute and chronic type B dissection is safe and effective at early midterm follow-up. TEVAR for type B dissection requires more secondary interventions and imaging surveillance than conventional open reconstruction. Longer-term follow-up is needed to determine the durability of this approach.

Does Negative Pressure Wound Therapy Have a Role in Preventing Poststernotomy Wound Complications

Background: Sternal wound infection (SWI) remains a devastating complication after cardiac surgery, decreasing long-term and short-term survival. In treating documented SWI, negative pressure wound therapy (NPWT) reduces wound edema and time to definitive closure and improves peristernal blood flow after internal mammary artery (IMA) harvesting. The authors evaluated NPWT as a form of “well wound” therapy in patients at substantial risk for SWI based on existing risk stratification models. Methods: Records of 57 adult cardiac surgery patients (September 2006 to April 2008) were reviewed. After preoperative risk assessment, NPWT was instituted on the clean, closed sternotomy immediately after surgery and continued 4 days postoperatively. Adverse postoperative events, including SWI, need for readmission, and other complications, were documented. Results: Mean age was 60.4 ± 10 years, and 89.5% were male; 77.2% were obese (mean body mass index 35.3 ± 6.7), 54.4% were diabetic, and 29 (50.9%) were both obese and diabetic. Coronary artery bypass (CAB) with single IMA was performed in 50.9% of the patients followed in frequency by combined CAB/valve, non-CAB surgery, and CAB with bilateral IMA. Estimated risk for SWI was 6.1 ± 4%. All patients tolerated NPWT to completion. Thirty-day and in-hospital mortality was 1.8% and unrelated to DSWI. No treatment of SWI was required. Conclusions: In this high-risk cohort, 3 postoperative SWI cases were anticipated but may have been mitigated by NPWT. This is an easily applied and well-tolerated therapy and may stimulate more effective wound healing. Among patients with increased SWI risk, strong consideration should be given to NPWT as a form of “well wound” therapy.

Neovascularization after transmyocardial laser revascularization in a model of chronic ischemia

BACKGROUND The mechanism of clinical improvement after transmyocardial laser revascularization (TMR) is unknown. One hypothesis holds that TMR causes increased myocardial perfusion through neovascularization. This study sought to determine whether angiogenesis occurs after TMR in a porcine model of chronic myocardial ischemia. METHODS Six miniature pigs underwent subtotal left circumflex coronary artery occlusion to reduce resting blood flow to 10% of baseline. After 2 weeks in the low-flow state, dobutamine stress echocardiography and positron emission tomography were performed to document ischemic, viable myocardium. The animals then underwent TMR and were sacrificed 6 months later for histologic and immunohistochemical analysis. RESULTS Histologic analysis of the lased left circumflex region demonstrated many hypocellular areas filled with connective tissue representing remnant TMR channels. Histochemical staining demonstrated a highly disorganized pattern of neovascularization consistent with angiogenesis located predominantly at the periphery of the channels. Immunohistochemical analysis confirmed the presence of endothelial cells within neovessels. Vascular density analysis revealed a mean of 29.2+/-3.6 neovessels per high-power field in lased ischemic myocardium versus 4.0+/-0.3 (p<0.001) in nonlased ischemic myocardium. CONCLUSIONS This study provides evidence that neovascularization is present long term in regions of ischemic, viable myocardium after TMR. Angiogenesis may represent the mechanism of clinical improvement after TMR.

Retrograde ascending aortic dissection as an early complication of thoracic endovascular aortic repair

OBJECTIVE Retrograde ascending aortic dissection (rAAD) is a potential complication of thoracic endovascular aortic repair (TEVAR), yet little data exist regarding its occurrence. This study examines the incidence, etiology, and outcome of this event. METHODS A prospective institutional database was used to identify cases of acute rAAD following TEVAR from a cohort of 309 consecutive procedures from March 2005 (date of initial Food and Drug Administration approval) to September 2010. The database was analyzed for the complication of rAAD as well as relevant patient and operative variables. RESULTS The incidence of rAAD was 1.9% (6/309); all cases occurred with proximal landing zone in the ascending aorta and/or arch (zones 0-2). All were identified in the perioperative period (range, 0-6 days) with 33% (2/6) 30-day/in-hospital mortality. Eighty-three percent (5/6) underwent emergent repair; one patient died without repair. rAAD patients were similar to the non-rAAD group (n = 303) across pertinent variables, including age, gender, race, and device size (all P > .1). rAAD incidence by aortic pathology was 1.0% (2/200) for aneurysm, 4.4% (4/91) for dissection, and 0% (0/18) for transection; P = .08. rAAD incidence by device was TAG (Gore) 1.0% (2/205), Talent (Medtronic) 4.7% (2/43), and Zenith TX2 (Cook) 3.6% (2/55). rAAD incidence was observed to be higher among patients with an ascending aortic diameter ≥ 4.0 cm (4.8% vs 0.9% for ascending diameter <4.0 cm); P = .047. Incidence was also higher with proximal landing zone in the native ascending aorta (zone 0) 6.9% (2/29) versus 1.4% for all others (4/280); P = .101. For patients with dissection pathology and an ascending aortic diameter ≥ 4.0 cm, 11% (3/28) suffered rAAD; with the combination of native ascending aorta (zone 0) landing zone measuring ≥ 4.0 cm, the incidence was 25% (2/8). Definitive diagnosis was by computed tomography angiography (n = 1), intraoperative transesophageal echocardiography (n = 3), intraoperative arteriography (n = 1), or postmortem autopsy (n = 1). CONCLUSIONS rAAD is a lethal early complication of TEVAR, which may be more common when treating dissection, with devices utilizing proximal bare springs or barbs for fixation, with native zone 0 proximal landing zone and with ascending aortic diameter ≥ 4 cm. Combinations of these risk factors may be particularly high risk. Intraoperative imaging assessment of the ascending aorta should be conducted following TEVAR to avoid under-recognition. National database reporting of this complication is needed to ensure safety and proper application of emerging TEVAR technology.

Contemporary results for proximal aortic replacement in North America.

OBJECTIVES The purpose of this study was to characterize operative outcomes for ascending aorta and arch replacement on a national scale and to develop risk models for mortality and major morbidity. BACKGROUND Contemporary outcomes for ascending aorta and arch replacement in North America are unknown. METHODS We queried the Society of Thoracic Surgeons Database for patients undergoing ascending aorta (with or without root) with or without arch replacement from 2004 to 2009. The database captured 45,894 cases, including 12,702 root, 22,048 supracoronary ascending alone, 6,786 ascending plus arch, and 4,358 root plus arch. Baseline characteristics and clinical outcomes were analyzed. A parsimonious multivariable logistic regression model was constructed to predict risks of mortality and major morbidity. RESULTS Operative mortality was 3.4% for elective cases and 15.4% for nonelective cases. A risk model for operative mortality (c-index 0.81) revealed a risk-adjusted odds ratio for death after emergent versus elective operation of 5.9 (95% confidence interval: 5.3 to 6.6). Among elective patients, end-stage renal disease and reoperative status were the strongest predictors of mortality (adjusted odds ratios: 4.0 [95% confidence interval: 2.6 to 6.4] and 2.3 (95% confidence interval: 1.9 to 2.7], respectively; p < 0.0001). CONCLUSIONS Current outcomes for ascending aorta and arch replacement in North America are excellent for elective repair; however, results deteriorate for nonelective status, suggesting that increased screening and/or lowering thresholds for elective intervention could potentially improve outcomes. The predictive models presented may serve clinicians in counseling patients.

Midterm results with thoracic endovascular aortic repair for chronic type B aortic dissection with associated aneurysm.

OBJECTIVE Thoracic endovascular aortic repair for chronic type B aortic dissection with associated descending thoracic aneurysm remains controversial. Concerns include potential ischemic complications due to branch vessel origin from the chronic false lumen and continued retrograde false lumen/aneurysm sac pressurization via fenestrations distal to implanted endografts. The present study examines midterm results with thoracic endovascular aortic repair for chronic (>2 weeks) type B aortic dissection with associated aneurysm to better understand the potential role of thoracic endovascular aortic repair for this condition. METHODS Between March 2005 and December 2009, 51 thoracic endovascular aortic repair procedures were performed at a single institution for management of chronic type B dissection. The indication for thoracic endovascular aortic repair was aneurysm in all cases. A subset of 7 patients (14%) underwent placement of the EndoSure wireless pressure measurement system (CardioMEMS, Inc, Atlanta, Ga) in the false lumen adjacent to the primary tear for monitoring aneurysm sac/false lumen pulse pressure after thoracic endovascular aortic repair. RESULTS Mean patient age was 57±12 years (range, 30-82 years); 14 patients (28%) were female. Mean aortic diameter was 6.2±1.4 cm. There were no in-hospital/30-day deaths, strokes, or permanent paraplegia/paresis. There were no complications related to compromise of downstream branch vessels arising from the false lumen. Two patients (3.9%) who had preexisting ascending aortic dilation had retrograde acute type A aortic dissection; both were repaired successfully. Median postoperative length of stay was 4 days. Mean follow-up is 27.0±16.5 months (range, 2-60 months). Actuarial overall survival is 77.7% at 60 months with an actuarial aorta-specific survival of 98% over this same time period. Actuarial freedom from reintervention is 77.3% at 60 months. All patients with the EndoSure wireless pressure measurement system exhibited a decrease in aneurysm sac/false lumen pulse pressure indicating a depressurized false lumen. The aneurysm sac/false lumen pulse pressure ratio decreased from 52%±27% at the predischarge measurement to 14%±5% at the latest follow-up reading (P=.029). CONCLUSIONS Thoracic endovascular aortic repair for chronic type B dissection with associated aneurysm is safe and effective at midterm follow-up. Aneurysm sac/false lumen pulse pressure measurements demonstrate a significant reduction in false lumen endotension, thus ruling out clinically significant persistent retrograde false lumen perfusion and provide proof of concept for a thoracic endovascular aortic repair-based approach. Longer-term follow-up is needed to determine the durability of thoracic endovascular aortic repair for this aortic pathology.

Results with an algorithmic approach to hybrid repair of the aortic arch

OBJECTIVE Hybrid repair of the transverse aortic arch may allow for aortic arch repair with reduced morbidity in patients who are suboptimal candidates for conventional open surgery. We present our results with an algorithmic approach to hybrid arch repair, based on the extent of aortic disease and patient comorbidities. METHODS Between August 2005 and January 2012, 87 patients underwent hybrid arch repair by three principal procedures: zone 1 endograft coverage with extra-anatomic left carotid revascularization (zone 1; n = 19), zone 0 endograft coverage with aortic arch debranching (zone 0; n = 48), or total arch replacement with staged stented elephant trunk completion (stented elephant trunk; n = 20). RESULTS The mean patient age was 64 years, and the mean expected in-hospital mortality rate was 16.3% as calculated by the EuroSCORE II. Of operations, 22% (n = 19) were nonelective. Sternotomy, cardiopulmonary bypass, and deep hypothermic circulatory arrest were required in 78% (n = 68), 45% (n = 39), and 31% (n = 27) of patients to allow for total arch replacement, arch debranching, or other concomitant cardiac procedures, including ascending with or without hemiarch replacement in 17% (n = 8) of patients undergoing zone 0 repair. All stented elephant trunk procedures (n = 20) and 19% (n = 9) of zone 0 procedures were staged, with 41% (n = 12) of patients undergoing staged repair during a single hospitalization. The 30-day/in-hospital rates of stroke and permanent paraplegia or paraparesis were 4.6% (n = 4) and 1.2% (n = 1). Of 27 patients with native ascending aorta zone 0 proximal landing zone, three (11.1%) experienced retrograde type A dissection after endograft placement. The overall in-hospital mortality rate was 5.7% (n = 5); however, 30-day/in-hospital mortality increased to 14.9% (n = 13) owing to eight 30-day out-of-hospital deaths. Native ascending aorta zone 0 endograft placement was found to be the only univariate predictor of 30-day in-hospital mortality (odds ratio, 4.63; 95% confidence interval, 1.35-15.89; P = .02). Over a mean follow-up period of 28.5 ± 22.2 months, 13% (n = 11) of patients required reintervention for type 1A (n = 4), type 2 (n = 6), or type 3 (n = 1) endoleak. Kaplan-Meier estimates of survival at 1 year, 3 years, and 5 years were 73%, 60%, and 51%. CONCLUSIONS Hybrid aortic arch repair can be tailored to patient anatomy and comorbid status to allow complete repair of aortic pathology, frequently in a single stage, with acceptable outcomes. However, endograft placement in the native ascending aorta is associated with high rates of retrograde type A dissection and 30-day/in-hospital mortality and should be approached with caution.

Five-year results for endovascular repair of acute complicated type B aortic dissection

INTRODUCTION Despite a current lack of U.S. Food and Drug Administration approval for the indication, thoracic endovascular aortic repair (TEVAR) has replaced open surgical management for acute complicated type B aortic dissection due to promising short- and midterm data. However, long-term results, with a view toward durability and need for secondary procedures, are limited. As such, the objective of the present study is to report long-term outcomes of TEVAR for acute (≤ 2 weeks from symptom onset) complicated type B dissection. METHODS Between July 2005 and September 2012, 50 consecutive patients underwent TEVAR for management of acute complicated type B dissection at a single referral institution. Patient records were retrospectively reviewed from a prospectively maintained clinical database. RESULTS Indications for intervention included rupture in 10 (20%), malperfusion in 24 (48%), and/or refractory pain/impending rupture in 17 (34%). One patient (2%) had both rupture and malperfusion indications. Ten (20%) patients required one or more adjunctive procedures, in addition to TEVAR, to treat malperfusion syndromes. In-hospital and 30-day rates of death were both 0%; 30-day/in-hospital rates of stroke, permanent paraplegia/paraparesis, and new-onset dialysis were 2% (n = 1), 2% (n = 1), and 4% (n = 2), respectively. Median follow-up was 33.8 months [interquartile range, 12.3-56.6 months]. Overall survival at 5 and 7 years was 84%, with no deaths attributable to aortic pathology. Thirteen (26%) patients required a total of 17 reinterventions over the study period for type I endoleak (n = 5), metachronous aortic pathology (n = 5), persistent false lumen pressurization via distal fenestrations (n = 4), type II endoleak (n = 2), or retrograde acute type A aortic dissection (n = 1). Median time to first reintervention was 4.5 months (range, 0 days-40.3 months). Of the 17 total reinterventions, six (35%) were performed using open techniques and 11 (65%) with endovascular or hybrid methods; there was no difference in survival between patients who did or did not require reintervention. CONCLUSIONS This study confirms the excellent short-term outcomes of TEVAR for acute complicated type B dissection and demonstrates the results to be durable and sustained over long-term follow-up. Although aortic reinterventions were required in one-quarter of patients, no aortic-related deaths were observed. These data support the use of TEVAR for acute complicated type B aortic dissection but also highlight the importance of life-long aortic surveillance by an experienced aortic referral center in order to identify and treat complications of the underlying disease process and treatment, as well as new aortic pathologies, as they arise.