Machine learning models for mitral valve replacement: A comparative analysis with the Society of Thoracic Surgeons risk score.

BACKGROUND: Current Society of Thoracic Surgeons (STS) risk models for predicting outcomes of mitral valve surgery (MVS) assume a linear and cumulative impact of variables. We evaluated postoperative MVS outcomes and designed mortality and morbidity risk calculators to supplement the STS risk score. METHODS: Data from the STS Adult Cardiac Surgery Database for MVS was used from 2008 to 2017. The data included 383,550 procedures and 89 variables. Machine learning (ML) algorithms were employed to train models to predict postoperative outcomes for MVS patients. Each model's discrimination and calibration performance were validated using unseen data against the STS risk score. RESULTS: Comprehensive mortality and morbidity risk assessment scores were derived from a training set of 287,662 observations. The area under the curve (AUC) for mortality ranged from 0.77 to 0.83, leading to a 3% increase in predictive accuracy compared to the STS score. Logistic Regression and eXtreme Gradient Boosting achieved the highest AUC for prolonged ventilation (0.82) and deep sternal wound infection (0.78 and 0.77) respectively. EXtreme Gradient Boosting performed the best with an AUC of 0.815 for renal failure. For permanent stroke prediction all models performed similarly with an AUC around 0.67. The ML models led to improved calibration performance for mortality, prolonged ventilation, and renal failure, especially in cases of reconstruction/repair and replacement surgery. CONCLUSIONS: The proposed risk models complement existing STS models in predicting mortality, prolonged ventilation, and renal failure, allowing healthcare providers to more accurately assess a patient's risk of morbidity and mortality when undergoing MVS.

On-X aortic valve replacement patients treated with low-dose warfarin and low-dose aspirin.

OBJECTIVES: To assess if warfarin targeted to international normalized ratio (INR) 1.8 (range 1.5-2.0) is safe for all patients with an On-X aortic mechanical valve. METHODS: This prospective, observational registry follows patients receiving warfarin targeted at an INR of 1.8 (range 1.5-2.0) plus daily aspirin (75-100 mg) after On-X aortic valve replacement. The primary end point is a composite of thromboembolism, valve thrombosis and major bleeding. Secondary end points include the individual rates of thromboembolism, valve thrombosis and major bleeding, as well as the composite in subgroups of home or clinic-monitored INR and risk categorization for thromboembolism. The control was the patient group randomized to standard-dose warfarin (INR 2.0-3.0) plus daily aspirin 81 mg from the PROACT trial. RESULTS: A total of 510 patients were enroled at 23 centres in the UK, USA and Canada. Currently, the median follow-up duration is 3.4 years, and median achieved INR is 1.9. The primary composite end point rate in the low INR patients is 2.31% vs 5.39% (95% confidence interval 4.12-6.93%) per patient-year in the PROACT control group, constituting a 57% reduction. Results are consistent in subgroups of home or clinic-monitored, and high-risk patients, with reductions of 56%, 57% and 57%, respectively. Major and total bleeding are decreased by 85% and 73%, respectively, with similar rates of thromboembolic events. No valve thrombosis occurred. CONCLUSIONS: Interim results suggest that warfarin targeted at an INR of 1.8 (range 1.5-2.0) plus aspirin is safe and effective in patients with an On-X aortic mechanical valve with or without home INR monitoring.

Low-dose warfarin with a novel mechanical aortic valve: Interim registry results at 5-year follow-up.

OBJECTIVES: To evaluate whether warfarin targeted at an international normalized ratio of 1.8 (range, 1.5-2.0) after On-X mechanical aortic valve implant is safe for all patients. METHODS: This prospective, observational clinical registry assessed adverse event rates in adult patients receiving low-dose warfarin (target international normalized ratio, 1.8; range, 1.5-2.0) plus daily aspirin (75-100 mg) during a 5-year period after On-X aortic valve implant. The primary end point is the combined rate of major bleeding, valve thrombosis, and thromboembolism overall and in 4 subgroups. The comparator is the Prospective Randomized On-X Anticoagulation Trial control group patients on standard-dose warfarin (international normalized ratio, 2.0-3.0) plus aspirin 81 milligrams daily. RESULTS: A total of 510 patients were recruited at 23 centers in the United States, United Kingdom, and Canada between November 2015 and January 2022. This interim analysis includes 229 patients scheduled to complete 5-year follow-up by August 16, 2023. The linearized occurrence rate (in percent per patient-year) of the primary composite end point of major bleeding, valve thrombosis, and thromboembolism is 1.83% compared with 5.39% (95% confidence interval, 4.12%-6.93%) in the comparator group. Results are consistent in clinic-monitored and home-monitored patients and in those at high risk for thromboembolism. Major bleeding and total bleeding were reduced by 87% and 71%, respectively, versus the comparator group, without an increase in thromboembolic events. CONCLUSIONS: Interim results support the continued safety of the On-X aortic mechanical valve with a target international normalized ratio of 1.8 plus low-dose aspirin through 5 years after implant, with or without home monitoring.

Vacuum assisted vegetation extraction for the management of large lead vegetations.

BACKGROUND: Complete device and lead removal is recommended for management of infected implantable cardiac device. Management of large lead vegetation (2 cm) is still in debate. METHODS: We report a series of patients involving percutaneous extraction of large vegetations (>2 cm) from ICD/pacing leads using the AngioVac Cannula in patients with infective endocarditis. This approach was used to debulk the ICD/pacing lead vegetations in order to minimize the risk of septic pulmonary embolism during lead explantation. CONCLUSION: AngioVac Cannula can be used safely and effectively as an adjunctive method for patients with large lead vegetation.

Intermediate Follow-Up of Balloon-Expandable Versus Self-Expanding Transcatheter Aortic Valve Implantation in Patients With Small Aortic Annuli.

The clinical impact of prosthesis-patient mismatch (PPM) in patients with small aortic annuli who underwent transcatheter aortic valve (AV) implantation with either balloon-expandable (BE) or self-expanding (SE) valves remains controversial. We assessed in-hospital and intermediate clinical outcomes in 573 patients with transfemoral transcatheter AV implantation with a small AV annulus, defined as an AV annulus area ≤430 mm2. A total of 337 patients treated with a 23-mm BE valve (SAPIEN 3, Ultra) were compared with 236 patients treated with a 26-mm SE valve (Evolut series). Valve-in-valve cases were excluded, and late echo follow-up (mean 674 ± 438 days) was assessed in a subset of 292 patients (51.0%). Well-matched BE and SE cohorts did not differ with respect to major in-hospital outcomes, other than a borderline increase in vascular complications and composite bleeding in patients with SE. Patients with BE had a higher incidence of severe PPM on discharge echocardiography (16.9% vs 6.8%, p <0.002). The mean AV gradient at 30 days was higher for patients with BE (12.2 ± 4.2 vs 6.2 ± 7.9 mm Hg, p <0.001) and at late follow-up (14.0 ± 8.2 vs 7.2 ± 3.5 mm Hg, p <0.001). The follow-up left ventricular ejection fraction and incidence of >mild aortic insufficiency were similar. All-cause mortality for the 2 cohorts was similar, with an overall mean (95% confidence interval) survival time of 61.2 months (57.8 to 64.5; p = 0.98). There were no significant survival differences between combined patients with BE and SE with no, moderate, or severe PPM, with an overall mean (95% confidence interval) survival time of 32.5 (30.5 to 34.5) months combining valve types (p = 0.23). In conclusion, despite an increased incidence of PPM with higher mean AV gradients that persist on late echocardiography in the BE cohort, patients with BE and SE with small aortic annuli have similar clinical outcomes at intermediate follow-up. Moderate and severe PPM had no impact on survival at a mean follow-up of 32.5 months.

Low-Dose vs Standard Warfarin After Mechanical Mitral Valve Replacement: A Randomized Trial.

BACKGROUND: Current guidelines recommend a target international normalized ratio (INR) range of 2.5 to 3.5 in patients with a mechanical mitral prosthesis. The Prospective Randomized On-X Anticoagulation Clinical Trial (PROACT) Mitral randomized controlled noninferiority trial assessed safety and efficacy of warfarin at doses lower than currently recommended in patients with an On-X (Artivion, Inc) mechanical mitral valve. METHODS: After On-X mechanical mitral valve replacement, followed by at least 3 months of standard anticoagulation, 401 patients at 44 North American centers were randomized to low-dose warfarin (target INR, 2.0-2.5) or standard-dose warfarin (target INR, 2.5-3.5). All patients were prescribed aspirin, 81 mg daily, and encouraged to use home INR testing. The primary end point was the sum of the linearized rates of thromboembolism, valve thrombosis, and bleeding events. The design was based on an expected 7.3% event rate and 1.5% noninferiority margin. RESULTS: Mean patient follow-up was 4.1 years. Mean INR was 2.47 and 2.92 (P <.001) in the low-dose and standard-dose warfarin groups, respectively. Primary end point rates were 11.9% per patient-year in the low-dose group and 12.0% per patient-year in the standard-dose group (difference, -0.07%; 95% CI, -3.40% to 3.26%). The CI >1.5%, thus noninferiority was not achieved. Rates (percentage per patient-year) of the individual components of the primary end point were 2.3% vs 2.5% for thromboembolism, 0.5% vs 0.5% for valve thrombosis, and 9.13% vs 9.04% for bleeding. CONCLUSIONS: Compared with standard-dose warfarin, low-dose warfarin did not achieve noninferiority for the composite primary end point. (PROACT Clinicaltrials.gov number, NCT00291525).

Transcarotid Versus Transfemoral Transcatheter Aortic Valve Replacement (from a Propensity-Matched Comparison).

Previous reports comparing transcarotid (TC) versus transfemoral (TF) approaches for patients undergoing transcatheter aortic valve replacement have had inconsistent conclusions. We compared in-hospital and 1-year clinical outcomes, changes in quality of life, and direct hospital costs for 138 TC versus 1,926 TF procedures. Propensity matching based on the Society of Thoracic Surgery Predicted Risk of Mortality was used to compare 130 patients who underwent TC with 813 patients who underwent TF. Matched TC versus TF cohorts did not differ with respect to in-hospital mortality (0.0% vs 1.4%, p = 0.380), stroke (2.3% vs 2.5%, p = 0.917), major vascular complications (0.8% vs 2.2%, p = 0.268), composite bleeding complications (4.6% vs 6.4%, p = 0.647), requirement for permanent pacemaker (14.6% vs 12.9%, p = 0.426), postoperative hospital length of stay (3.3 ± 3.4 vs 3.1 ± 3.3 days, p = 0.467), or direct hospital costs ($52,899 ± 9,560 vs $50,464 ± 10,997, p = 0.230). Similarly, at 1-year, patients who underwent TC versus patients who underwent TF did not differ with respect to all-cause mortality (7.6% vs 6.4%, p = 0.659), hospital readmission (20.0% vs 23.9%, p = 0.635), or quality of life as measured by the Kansas City Cardiomyopathy Questionnaire score (84.0 ± 17.1 vs 88.4 ± 13.9, p = 0.062). Patients who underwent TC and TF did not differ with respect to in-hospital complications, length of hospital stay, and direct hospital costs, as well as 1-year mortality, readmission, and quality of life. These data add to ongoing support for the TC approach as the optimal alternative access for patients with transcatheter aortic valve replacement deferred from a transfemoral approach.

WITHDRAWN: Low-Dose Versus Standard Warfarin After Mechanical Mitral Valve Replacement: A Randomized Controlled Trial.

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Effects of cardiopulmonary bypass on endothelin-1-induced contraction and signaling in human skeletal muscle microcirculation.

BACKGROUND: We investigated the effects of cardiopulmonary bypass (CPB) on the contractile response of human peripheral microvasculature to endothelin-1 (ET-1), examined the role of specific ET receptors and protein kinase C-alpha (PKC-α), and analyzed ET-1-related gene/protein expression in this response. METHODS AND RESULTS: Human skeletal muscle arterioles (90 to 180 µm in diameter) were dissected from tissue harvested before and after CPB from 30 patients undergoing cardiac surgery. In vitro contractile response to ET-1 was assessed by videomicroscopy, with and without an endothelin-A (ET-A) receptor antagonist, an endothelin-B (ET-B) antagonist, or a PKC-α inhibitor. The post-CPB contractile response of peripheral arterioles to ET-1 was significantly decreased compared with pre-CPB response. The response to ET-1 was significantly inhibited in the presence of the ET-A antagonist BQ123 but unchanged in the presence of the ET-B receptor antagonist BQ788. Pretreatment with the PKC-α inhibitor safingol reversed ET-1-induced response from contraction to relaxation. The total protein levels of ET-A and ET-B receptors were not altered after CPB. Microarray analysis showed no significant changes in the gene expression of ET receptors, ET-1-related proteins, and protein kinases after CPB. CONCLUSIONS: CPB decreases myogenic contractile function of human peripheral arterioles in response to ET-1. The contractile response to ET-1 is through activation of ET-A receptors and PKC-α. CPB has no effects on ET-1-related gene/protein expression. These results provide novel mechanisms of ET-1-induced contraction in the setting of vasomotor dysfunction after cardiac surgery.

Open and endovascular repair of type B aortic dissection in the Nationwide Inpatient Sample.

BACKGROUND: The use of stent grafts and mortality of stent graft repair of type B thoracic aortic dissection (T(B)AD) is not well defined. We sought to determine national estimates for the use and mortality of thoracic endovascular aortic repair (TEVAR) for T(B)AD in the United States. METHODS: Records of the Nationwide Inpatient Sample (NIS) database between 2005 and 2007 were examined. International Classification of Diseases, 9th edition (ICD-9) diagnosis codes were used to select patients who underwent open or TEVAR with a stent graft for a diagnosis of thoracic aortic dissection or thoracoabdominal aortic dissection. We excluded patients with a diagnosis code for aortic aneurysm and those with procedure codes for cardioplegia or for operations on heart vessels or valves, which were considered type A dissections (T(A)AD). The remaining patients were considered as T(B)AD. We compared demographics and comorbidities, as well as adjusted complications and mortality rates, between patients undergoing TEVAR vs open repair. RESULTS: We identified an estimated 10,466 repairs for dissection of the thoracic or thoracoabdominal aorta (open, 8659; TEVAR, 1818). Of these, 464 had a diagnosis of aortic aneurysm, and 5002 patients were considered T(A)AD. Of nonaneurysmal dissections, 5000 repairs were considered T(B)AD (open, 3619; TEVAR, 1381). The endovascular patients were older and had greater comorbidities, although only cardiac disease, renal failure, hypertension, and peripheral vascular disease were statistically significant. In-hospital mortality was 19% for open repair vs 10.6% for TEVAR (odds ratio [OR], 2.24; 95% confidence interval [CI], 1.36-3.67; P < .01). In-hospital mortality was significantly higher with open repairs coded as emergent admissions (20.1% vs 13.1%; P = .03), but did not reach statistical significance for elective admissions (12.3% vs 4.8%; P = .09). Cardiac complications (12.4% vs 4.9%, P < .01), respiratory complications (7.7% vs 4.3%, P = .02), genitourinary complications (9.0% vs 2.5%, P < .01), hemorrhage (14.0% vs 2.8%, P < .01), and acute renal failure (32.1% vs 17.2%, P < .01) were more frequent in the open repair group. Median length of stay was greater in the open repair group (10.7 vs 8.3 days, P < .01). CONCLUSION: For patients with a diagnosis of T(B)AD who undergo repair, the endovascular approach is being used for older patients with greater comorbidities, yet has reduced morbidity and in-hospital mortality. The use of endovascular stent graft repair for type B thoracic aortic dissection merits further longitudinal analysis.

Hybrid myocardial revascularization: an integrated approach to coronary revascularization.

Coronary artery bypass surgery is beneficial in patients with complex coronary artery disease. The longevity of the left internal mammary artery (LIMA) placed to the left anterior descending (LAD) artery (LIMA-LAD) is between 92-99% at 15 years, and contributes substantially to the survival advantage in patients treated with surgical revascularization. The long-term patency of saphenous vein grafts (SVGs), commonly used (>95%) in surgical revascularization procedures, is less well-established, with up to 26% of SVGs failing in the first year. In selected patients, particularly in those patients with vessels poorly suited to SVGs, hybrid myocardial revascularization (HMR) has been used, combining a minimally invasive approach to the LIMA-LAD with drug-eluting stent placement of the non-LAD vessels. The advantages and disadvantages of hybrid myocardial revascularization are reviewed in this report.

Large conductance calcium-activated potassium channels contribute to the reduced myogenic tone of peripheral microvasculature after cardiopulmonary bypass.

BACKGROUND: We investigated the role of calcium-activated potassium (K(Ca)) channel activation in myogenic tone in human peripheral microvasculature after heart surgery. METHODS: Human skeletal muscle arterioles (90-180microm diameter) were dissected from tissue harvested pre- and post-cardiopulmonary bypass (CPB) during cardiac surgery. Myogenic reactivity in response to stepwise increases in intraluminal pressure was studied between pressure steps. Microvessel tone was determined pre-CPB, post-CPB, and after blockade of K(Ca) channels. Expression and localization of large conductance (BK) K(Ca) channels in the coronary microvasculature was assessed by immunoblot and immunofluorescence photomicroscopy. RESULTS: Myogenic tone of skeletal muscle arterioles was significantly reduced post-CPB compared with pre-CPB. Decrease in myogenic tone after CPB was reflected by the increase in microvessel internal diameter. Myogenic tone of post-CPB microvessels was significantly increased after treatment with BK(Ca)-blocker iberiotoxin, but unchanged in the combined presence of the blockers of intermediate (IK(Ca)) and small conductance (SK(Ca)) K(Ca) channels, TRAM34/apamin. The increases in myogenic tone after iberiotoxin treatment were demonstrated as a decrease in microvessel internal diameter. No significant differences in BK(Ca) protein levels were noted comparing pre- and post-CPB conditions judged by immunoblot and by immunofluorescence staining of skeletal muscle microvessels. Prominent staining for BK(Ca)-alpha and BK(Ca)-beta(1) subunits localized to the microvascular smooth muscle. CONCLUSION: CPB-associated decrease in peripheral myogenic reactivity is likely due to activation of BK(Ca), but not IK(Ca) or SK(Ca). CPB may increase BK(Ca) activity without increasing BK polypeptide level.

Population-based outcomes of open descending thoracic aortic aneurysm repair.

OBJECTIVE: To evaluate national outcomes after open repair of descending thoracic aortic aneurysm (DTA). METHODS: The DTA repairs were identified from the NIS database from 1988-2003 by ICD9 codes for thoracic vascular resection and replacement (38.45) and a diagnosis of intact (441.1) or ruptured (441.2) thoracic aortic aneurysm; excluding thoraco-abdominal aneurysm, abdominal aortic aneurysm repair, cardioplegia, hypothermia, cardiac surgery, or aorta to carotid or subclavian bypass. Demographics and comorbidities were noted. Outcomes included in-hospital mortality, length of stay, and complications. Annual hospital surgical volume terciles (high, medium, and low) were quantified for the series and patients assigned accordingly. Outcomes were compared between intact and ruptured aneurysm characteristics as well as annual hospital volume. Predictors of peri-operative mortality were analyzed by multivariate logistic regression. RESULTS: A total of 2549 DTA repairs were identified (1976 intact, 573 ruptured). Mortality was 18% overall; 10% for intact (age <65 6.2%, 65-74 11.3%, >/=75 17.6%, P < .001), 45% for ruptured (age <65 33.3%, 65-74 47.1%, >/=75 52.4%, P < .001). Mortality decreased over the 15-year time-period (P < .0001). Mortality after intact repair was lower at a high volume hospital (HVH) (8%) than a low volume hospital (LVH) (13%) or medium volume hospital (MVH) (12%). Hospital volume tercile did not predict rupture mortality. Complications after intact DTA repair were coded in 42%; including respiratory (13%), cardiac (11%), acute renal failure (8%), stroke (3%), and neurologic (non-stroke) (2%). Complications were coded in 49% after ruptured DTA repair including respiratory (13%), cardiac (13%), acute renal failure (20%), stroke (3%), and neuro (non-stroke) (2%). Predictors of mortality (for all DTA repairs) were (odd ratio [OR], 95% confidence interval [CI]): age 65-74 vs age <65 (1.8, 1.4-2.4), age >/=75 vs age <65 (2.7, 2.0-3.6), rupture (6.3, 5.1-7.9), and LVH or MVH vs HVH (1.3, 1.1-1.7). CONCLUSION: Mortality after open repair of DTA is high and complications are common. Mortality is dependent upon age, rupture status, and hospital surgical volume. Results of endovascular DTA repair should be compared using similar population-based data.

Quantification of Postmembrane Gaseous Microembolization During Venoarterial Extracorporeal Membrane Oxygenation.

Prolonged use of venoarterial extracorporeal membrane oxygenation (VA ECMO) may be complicated by end-organ dysfunction. Although gaseous microemboli (GME) are thought to damage end organs during cardiopulmonary bypass, patient exposures to GME have not been well characterized during VA ECMO. We therefore performed an observational study of GME in adult VA ECMO patients, with correlation to clinical events during routine patient care. After institutional review board (IRB) approval, we used two Doppler probes to detect GME noninvasively in extracorporeal membrane oxygenation (ECMO) circuits on four patients for 15 hours total while also recording patient care events. We then conducted in vitro trials to compare Doppler signals with gold-standard measurements using an Emboli Detection and Classification EDAC quantifier (Luna Innnovations, Inc. Roanoke, VA) (Terumo Cardiovascular, Ann Arbor, MI) during simulated clinical interventions. Correlations between Doppler and EDAC data were used to estimate GME counts and volumes represented by clinical Doppler data. A total of 503 groups of Doppler peaks representing GME showers were observed, including 194 statistically larger showers during patient care activities containing 92% of total Doppler peaks. Intravenous injections accounted for an estimated 68% of GME and 88% of GME volume, whereas care involving movement accounted for an estimated 6% of GME and 3% of volume. Overall estimated embolic rates of 24,000 GME totaling 4 µl/hr rivals reported GME rates during cardiopulmonary bypass. Numerous GME are present in the postmembrane circuit during VA ECMO, raising concern for effects on microcirculation and organ dysfunction. Strategies to detect and minimize GME may be warranted to limit embolic exposures experienced by VA ECMO patients.

Subclavian/Axillary Access for Self-Expanding Transcatheter Aortic Valve Replacement Renders Equivalent Outcomes as Transfemoral.

BACKGROUND: Iliofemoral arterial disease can preclude transfemoral (TF) transcatheter aortic valve replacement (TF-TAVR). Transthoracic access by direct aortic or a transapical approach imparts a greater risk of complications and death than TF access. We hypothesized that subclavian/axillary arterial (SCA) access offers equivalent risks and outcomes as TF access. METHODS: The outcomes of 202 patients from the CoreValve (Medtronic, Minneapolis, MN) United States Pivotal Trial Program treated with SCA access were propensity matched with patients treated with TF access and analyzed. RESULTS: Matching was successful, with no significant baseline differences in the SCA group and the TF group, except the SCA group had more past or present smokers (79.2% vs 61.4%, p < 0.001) and fewer patients with anemia requiring transfusion (18.5% vs 27.5%, p = 0.04). SCA patients experienced a significantly longer time from enrollment to procedure (8.6 ± 19.1 vs 5.3 ± 6.3 days; p = 0.02), likely the result of case planning. Significant differences in procedural outcomes include less post-TAVR balloon dilation (17.9% vs 26.7%, p = 0.03) and more general anesthesia (99.0% vs 89.6%, p < 0.001) for the SCA accesses. There were no differences in procedure time (57.8 ± 45.3 vs 57.5 ± 32.1 min, p = 0.94) or Valve Academic Research Consortium I-defined procedure success between groups (p = 0.89). Event rates at 30 days or 1 year were similar, with a trend toward fewer pacemakers with SCA accesses. CONCLUSIONS: Major morbidity and mortality rates SCA-TAVR are equivalent to TF-TAVR. The SCA should be the preferred secondary access site for TAVR because it offers procedural and clinical outcomes comparable to TF-TAVR and applies to most patients who are not TF candidates.

Anticoagulation and Antiplatelet Strategies After On-X Mechanical Aortic Valve Replacement.

BACKGROUND: The burden oral anticoagulation is a limitation of mechanical valve prostheses. OBJECTIVES: The aim of this study was to test whether patients could be safely managed with dual-antiplatelet therapy (DAPT) (aspirin 325 mg and clopidogrel 75 mg) or lower warfarin after On-X mechanical aortic valve replacement (mAVR). METHODS: PROACT (Prospective Randomized On-X Anticoagulation Trial) (n = 576) is a multicenter (41 sites) noninferiority trial. From June 2006 through February 2014, 201 patients ≥18 years of age without thromboembolic risk factors undergoing mAVR were randomized to receive DAPT (n = 99) or standard warfarin plus aspirin (n = 102) 3 months after mAVR (low-risk arm). From June 2006 through October 2009, 375 patients with 1 or more thromboembolic risk factors were also randomized to lower intensity warfarin plus aspirin (international normalized ratio 1.5 to 2.0; n = 185) or standard warfarin plus aspirin (international normalized ratio 2.0 to 3.0; n = 190) 3 months after mAVR (high-risk arm). RESULTS: The low-risk arm was terminated for excess cerebral thromboembolic events (3.12% per patient-year vs. 0.29% per patient-year, p = 0.02) in the DAPT group at up to 8.8-year follow-up (631.6 patient-years), with no differences in bleeding or all-cause mortality. High-risk arm patients experienced significantly lower major (1.59% per patient-year vs. 3.94% per patient-year, p = 0.002) and minor (1.27% per patient-year vs. 3.49% per patient-year, p = 0.002) bleeding up to 8.7-year follow-up (2,035.2 patient-years), with no differences in thromboembolism (0.42% per patient-year vs. 0.09% per patient-year, p = 0.20) and all-cause mortality. CONCLUSIONS: DAPT was associated with higher rates of thromboembolism and valve thrombosis compared with control in the low-risk arm. International normalized ratios were safely maintained at 1.5 to 2.0 in high-risk patients, without differences in mortality or thromboembolic complications. (Randomized On-X Anticoagulation Trial [PROACT]; NCT00291525).

Severe and resistant hypertension in an older woman with claudication.

Coarctation of the aorta is an uncommon cause of treatment-resistant hypertension in adults. It is typically detected and treated in infancy or childhood with surgical or endovascular procedures. Most cases of recurrence of coarctation after repair occur in childhood or early adulthood; recurrence in older persons (>70 years) has rarely been reported. A 73-year-old woman was referred to us for the management of treatment-resistant hypertension accompanied by symptoms of claudication and headaches, which had resulted in multiple emergency room visits. Of note, 58 years earlier, a graft from the left subclavian artery had been used to bypass an aortic coarctation. During a hospitalization for severe hypertension accompanied by acute kidney injury and heart failure, diagnostic angiography revealed a complete thrombotic occlusion of the left subclavian-artery-to-descending-aorta bypass graft and a tight coarctation in the descending thoracic aorta. Balloon angioplasty and stenting across the coarctation was only transiently effective; subsequently, an ascending-to-descending graft was placed distal to the coarctation, and within a few days, the blood pressure levels and claudication improved markedly. This case demonstrates that hypertension specialists should suspect the possibility of recurrence of a coarctation in older patients who present with resistant hypertension and have a remote history of coarctation repair. Although such late recurrences are not common, as illustrated in our patient, surgical intervention may contribute to significant improvement in blood pressure control and prevent future complications.

Comparison between antegrade and retrograde cerebral perfusion or profound hypothermia as brain protection strategies during repair of type A aortic dissection.

BACKGROUND: The goal of this study was to compare early postoperative outcomes and actuarial-free survival between patients who underwent repair of acute type A aortic dissection by the method of cerebral perfusion used. METHODS: A total of 324 patients from five academic medical centers underwent repair of acute type A aortic dissection between January 2000 and December 2010. Of those, antegrade cerebral perfusion (ACP) was used for 84 patients, retrograde cerebral perfusion (RCP) was used for 55 patients, and deep hypothermic circulatory arrest (DHCA) was used for 184 patients during repair. Major morbidity, operative mortality, and 5-year actuarial survival were compared between groups. Multivariate logistic regression was used to determine predictors of operative mortality and Cox Regression hazard ratios were calculated to determine the predictors of long term mortality. RESULTS: Operative mortality was not influenced by the type of cerebral protection (19% for ACP, 14.5% for RCP and 19.1% for DHCA, P=0.729). In multivariable logistic regression analysis, hemodynamic instability [odds ratio (OR) =19.6, 95% confidence intervals (CI), 0.102-0.414, P<0.001] and CPB time >200 min(OR =4.7, 95% CI, 1.962-1.072, P=0.029) emerged as independent predictors of operative mortality. Actuarial 5-year survival was unchanged by cerebral protection modality (48.8% for ACP, 61.8% for RCP and 66.8% for no cerebral protection, log-rank P=0.844). CONCLUSIONS: During surgical repair of type A aortic dissection, ACP, RCP or DHCA are safe strategies for cerebral protection in selected patients with type A aortic dissection.

Techniques of Proximal Root Reconstruction and Outcomes Following Repair of Acute Type A Aortic Dissection.

BACKGROUND: The goal of this study was to compare the early and late outcomes of different techniques of proximal root reconstruction during the repair of acute Type A aortic dissection, including aortic valve (AV) resuspension, aortic valve replacement (AVR), and a root replacement procedure. METHODS: All patients who underwent acute Type A aortic dissection repair between January 2000 and October 2010 at four academic institutions were compiled from each institution's Society of Thoracic Surgeons Database. This included 189 patients who underwent a concomitant aortic valve (AV) procedure; 111, 21, and 57 patients underwent AV resuspension, AVR, and the Bentall procedure, respectively. The median age of patients undergoing a root replacement procedure was significantly younger than the other two groups. Early clinical outcomes and 10-year actuarial survival rates were compared. Trends in outcomes and surgical techniques throughout the duration of the study were also analyzed. RESULTS: The operative mortality rates were 17%, 29%, and 18%, for AV resuspension, AVR, and root replacement, respectively. Operative mortality (p = 0.459) was comparable between groups. Hemorrhage related re-exploration did not differ significantly between groups (p = 0.182); however, root replacement procedures tended to have decreased rates of bleeding when compared to AVR (p = 0.067). The 10-year actuarial survival rates for the AV resuspension, Bentall, and AVR groups were 72%, 56%, and 36%, respectively (log-rank p = 0.035). CONCLUSIONS: The 10-year actuarial survival was significantly lower in those receiving AVR compared to those receiving root replacement procedures or AV resuspension. Operative mortality was comparable between the three groups.

Axillary Versus Femoral Arterial Cannulation During Repair of Type A Aortic Dissection?: An Old Problem Seeking New Solutions.

BACKGROUND: The goal of this study was to compare early postoperative outcomes and actuarial-free survival between patients who underwent repair of acute Type A aortic dissection with axillary or femoral artery cannulation. METHODS: A total of 305 patients from five academic medical centers underwent acute Type A aortic dissection repair via axillary (n = 107) or femoral (n = 198) artery cannulation between January 2000 and December 2010. Major morbidity, operative mortality, and 5-year actuarial survival were compared between groups. Multivariate logistic regression was used to determine predictors of operative mortality, and Cox regression hazard ratios were calculated to determine predictors of long-term mortality. RESULTS: Operative mortality was not influenced by cannulation site (16% for axillary cannulation vs. 19% for femoral cannulation, p = 0.64). In multivariate logistic regression analysis, hemodynamic instability (p < 0.001) and prolonged cardiopulmonary bypass time (>200 min; p = 0.05) emerged as independent predictors of operative mortality. Stroke rates were comparable between the two techniques (14% for axillary and 17% for femoral cannulation, p = 0.52). Five-year actuarial survival was comparable between the groups (55.1% for axillary and 65.7% for femoral cannulation, p = 0.36). In Cox regression analysis, predictors of long-term mortality were: age (p < 0.001), stroke (p < 0.001), prolonged cardiopulmonary bypass time (p = 0.001), hemodynamic instability (p = 0.002), and renal failure (p = 0.001). CONCLUSIONS: The outcomes of femoral versus axillary arterial cannulation in patients with acute Type A aortic dissection are comparable. The choice of arterial cannulation site should be individualized based on different patient risk profiles.