2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation.

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Association of STS database variables with repair durability in ischemic mitral regurgitation using machine learning.

BACKGROUND: Machine learning (ML) can identify nonintuitive clinical variable combinations that predict clinical outcomes. To assess the potential predictive contribution of standardized Society of Thoracic Surgeons (STS) Database clinical variables, we used ML to detect their association with repair durability in ischemic mitral regurgitation (IMR) patients in a single institution study. METHODS: STS Database variables (n = 53) served as predictors of repair durability in ML modeling of 224 patients who underwent surgical revascularization and mitral valve repair for IMR. Follow-up mortality and echocardiography data allowed 1-year outcome analysis in 173 patients. Supervised ML analyses were performed using recurrence (≥3+ IMR) or death versus nonrecurrence (<3+ IMR) as the binary outcome classification. RESULTS: We tested standard ML and deep learning algorithms, including support vector machines, logistic regression, and deep neural networks. Following training, final models were utilized to predict class labels for the patients in the test set, producing receiver operating characteristic (ROC) curves. The three models produced similar area under the curve (AUC), and predicted class labels with promising accuracy (AUC = 0.72-0.75). CONCLUSIONS: Readily-available STS Database variables have potential to play a significant role in the development of ML models to direct durable surgical therapy in IMR patients.

Efficacy of the stand-alone Cox-Maze IV procedure in patients with longstanding persistent atrial fibrillation.

INTRODUCTION: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and results in significant morbidity and mortality. The Cox-Maze IV procedure (CMP-IV) has been shown to have excellent efficacy in returning patients to sinus rhythm, but there have been few reports of late follow-up in sizable cohorts of patients with longstanding persistent AF, the most difficult type of AF to treat. METHODS AND RESULTS: Between May 2003 and March 2020, 174 consecutive patients underwent a stand-alone CMP-IV for longstanding persistent AF. Rhythm outcome was assessed postoperatively for up to 10 years, primarily via prolonged monitoring (Holter monitor, pacemaker interrogation, or implantable loop recorder). Fine-Gray regression was used to investigate factors associated with atrial tachyarrhythmia (ATA) recurrence, with death as a competing risk. Median duration of preoperative AF was 7.8 years (interquartile range: 4.0-12.0 years), with 71% (124/174) having failed at least one prior catheter-based ablation. There were no 30-day mortalities. Freedom from ATAs was 94% (120/128), 83% (53/64), and 88% (35/40) at 1, 5, and 7 years, respectively. On regression analysis, preoperative AF duration and early postoperative ATAs were associated with late ATAs recurrence. CONCLUSION: Despite the majority of patients having a long-duration of preoperative AF and having failed at least one catheter-based ablation, the stand-alone CMP-IV had excellent late efficacy in patients with longstanding persistent AF, with low morbidity and no mortality. We recommend consideration of stand-alone CMP-IV for patients with longstanding persistent AF who have failed or are poor candidates for catheter ablation.

Surgery for Atrial Fibrillation.

Atrial fibrillation is the most common cardiac arrhythmia, and its treatment options include drug therapy or catheter-based or surgical interventions. The surgical treatment of atrial fibrillation has undergone multiple evolutions over the last several decades. The Cox-Maze procedure went on to become the gold standard for the surgical treatment of atrial fibrillation and is currently in its fourth iteration (Cox-Maze IV). This article reviews the indications and preoperative planning for performing a Cox-Maze IV procedure. This article also reviews the literature describing the surgical results for both approaches including comparisons of the Cox-Maze IV to the previous cut-and-sew method.

Surgical ablation for atrial fibrillation: techniques, indications, and results.

PURPOSE OF REVIEW: The aim of this review is to focus specifically on the indications, evolution of technique, and results of surgical ablation for atrial fibrillation. RECENT FINDINGS: With the introduction of the Cox-Maze IV procedure utilizing bipolar radiofrequency ablation and cryoablation, long-term studies have demonstrated a significant decrease in aortic cross-clamp times and major complications with a comparable rate of restoration of sinus rhythm. New hybrid approaches utilizing both catheter-based ablation and minimally invasive surgical approaches have been developed, but have not been standardized. Early studies have demonstrated reasonable success rates of hybrid procedures, with advantages that include confirmation of conduction block, decreased surgical morbidity, and possibly reduced morbidity. However, hybrid approaches have the disadvantage of significantly increased operative times. SUMMARY: The Cox-Maze IV is currently the gold standard for surgical treatment of atrial fibrillation. New hybrid approaches have potential advantages with promising early results, but a standard lesion set, improvement in operative times, and long-term results still need to be evaluated.

Left main disease progression following left branch vessel percutaneous intervention in patients who are referred for coronary artery bypass grafting.

BACKGROUND AND AIM OF THE STUDY: We studied patients presenting for coronary artery bypass grafting (CABG) with significant left main coronary artery disease (LMD) despite previously documented minimal or no LMD at percutaneous coronary intervention (PCI) for left-sided branch coronary artery disease. METHODS: Patients undergoing CABG for LMD with previous PCI were separated into fast or slow stenosis progression using percent change in LMD from first PCI to CABG divided by time (progression velocity). Outcomes and Kaplan-Meier survival were compared between the two groups. RESULTS: Between September 1997 and June 2010, 4837 patients underwent CABG with 1235 of them having previous PCI of which 118 had LMD and previous left-sided branch PCI. Using median progression velocity fast and slow progression groups were identified (0.53 ± 0.18 and 4.5 ± 4.8%/month, p < 0.001). Mean follow-up was 4.9 ± 3.6 years and 6.9 ± 3.9 years, respectively. Fast progression patients were younger (p = 0.042), with higher baseline LMD at PCI (16.4% vs. 9% stenosis, p = 0.025), and a mean of 2.5 years to LMD compared to 10.6 years for the slow group (p < 0.001). There was no difference between the groups in number or type of PCI and number or type of vessel intervened. Kaplan-Meier survival was similar at one, three, and five years. CONCLUSIONS: Fast LMD progression patients were younger and made up 4.7% (59/1235) of patients undergoing CABG with a history of PCI. Rapid progression was not related to number, type of PCI, or branch vessel intervened.

Efficacy of a Surgical Cardiac Ablation Clamp using Nanosecond Pulsed Electric Fields: An Acute Porcine Model.

OBJECTIVE: This study examined the effectiveness of a recently developed non-thermal technology, nanosecond pulse field ablation (nsPFA), for surgical ablation of the atria in a beating heart porcine model. METHODS: Six pigs underwent sternotomy and ablation using an nsPFA parallel clamp. The ablation electrodes (53 mm long) were embedded in the jaws of the clamp. Nine lesions per pig were created in locations chosen to be representative of the Cox-Maze procedure. Four lesions were intended to electrically isolate parts of the atrium: the right atrial appendage, left atrial appendage, right pulmonary veins, and left pulmonary veins. For these lesions, exit block testing was performed both after ablation and before euthanasia; the time between the two tests was 3.3±0.5 hours (range 2 to 4 hours). Using purse string sutures, five more lesions were created up to the superior vena cava, down to the inferior vena cava, across the right atrial free wall, and at two distinct locations on the left atrial free wall. The clamp delivered a train of nanosecond duration pulses, with a total duration of 2.5 s, independent of tissue thickness. The heart tissue was stained with 1% triphenyltetrazolium chloride (TTC) after a dwelling period of two hours. Subsequently, each lesion was cross sectioned at 5 mm intervals to assess the ablation depth and transmurality. In some sections, transmurality could not be established on the basis of TTC staining alone; for these lesions, Gomori-trichrome stains were used, and the histological sections were evaluated for transmurality. RESULTS: The ablation time was 2.5 seconds per lesion, for a total of only 22.5 seconds ablation time to create 9 lesions. A total of 53 lesions were created, resulting in 388 separate histological sections. Transmurality was established in 386 sections (99.5%). Mean tissue thickness was 3.1±1.5 mm (range of 0.2 mm to 8.6 mm). Exit block was confirmed in 23 of the 24 lesions (96%) post-ablation and 23/24 (96%) pre-euthanasia. Over the course of the procedure, neither pulse-induced arrhythmias nor any other complications were noted. CONCLUSIONS: The novel nsPFA clamp device was effective in creating acute conduction block and transmural lesions in both the right and left atria in an acute porcine model. This non-thermal energy source has great potential to both shorten procedural time and enable effective ablation in the beating heart.

Surgically implanted endovascular, microaxial left ventricular assist device: A single institution study.

Objective: The Impella 5.5 (Abiomed, Inc), a surgically implanted endovascular microaxial left ventricular assist device, is increasingly used worldwide and there have been more than 10,000 implants. The purpose of this study is to describe a large-volume, single-center experience with the use of the Impella 5.5. Methods: Data were obtained retrospectively from patients supported with the Impella 5.5 implanted at our institution from May 1, 2020, to December 31, 2022. Demographic, operative, and postoperative outcomes for each group are described. Results are reported in median (interquartile range) or n (%). The entire cohort was divided into 5 main groups based on the intention to treat at the time of the Impella 5.5 implantation: (1) patients who had a planned Impella 5.5 implanted at the time of high-risk cardiac surgery; (2) patients with cardiogenic shock; (3) patients bridged to a durable left ventricular assist device; (4) patients bridged to transplant; and (5) patients with postcardiotomy shock who received an unplanned Impella 5.5 implant. Results: A total of 126 patients were supported with the Impella 5.5. Overall survival to device explant was 76.2%, with 67.5% surviving to discharge. Midterm survival was assessed with a median follow-up time of 318 days and demonstrated an overall survival of 60.3% and a median of 650 days (549-752). Conclusions: Outcomes after using the Impella 5.5 are variable depending on the indication of use. Patient selection may be of utmost importance and requires further experience with this device to determine who will benefit from insertion.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation.

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation.

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

Radial artery free and T graft patency as coronary artery bypass conduit over a 15-year period.

BACKGROUND: The radial artery is often used as the second arterial graft for coronary artery bypass grafting. Little is known about the differences in long-term patency between radial free and T grafts. This study was performed to determine long-term radial artery patency over a 15-year period. METHODS AND RESULTS: Radial arteries were used as free grafts or T grafts for coronary artery bypass grafting over a 15-year period. Patients were contacted to determine if postoperative cardiac catheterization was performed and examination of any reports and films was performed. Grafts were graded as patent, luminal irregularity, or occluded. Each sequential graft was counted separately. Between September 1993 and December 2008, 13,926 patients underwent isolated coronary artery bypass grafting and 3248 patients had at least one radial artery graft used as a conduit. Catheterizations were performed at a mean of 7.4 ± 3.8 years (range, 3 days to 14.4 years) on 372 radial artery grafts (103 free and 269 T) in 215 patients. Kaplan-Meier freedom from occlusion for radial free and T grafts at 1 and 10 years was 97.1% and 75.4% and 99.6% and 62.9%, respectively (P=0.146 free versus T). Kaplan-Meier survival to 15 years was not statistically different between free and T graft patients (P=0.5). CONCLUSIONS: In 215 patients with postoperative catheterization after coronary artery bypass grafting with a radial artery graft, radial free and T grafts had similar and acceptable long-term patency to support their use as a coronary artery bypass graft conduit.

Surgical techniques used for the treatment of atrial fibrillation.

The use of surgical lesion sets for the treatment of atrial fibrillation has been increasing, particularly in patients with complicated anatomical substrates and those undergoing concomitant surgery. Preferences in terms of lesion set, surgical approach and ablation technology vary by center. This review discusses both the surgical techniques and the outcomes for the most commonly performed procedures in the context of recent consensus guidelines. The Cox-Maze IV, pulmonary vein isolation, extended left atrial lesion sets, the hybrid approach and ganglionated plexus ablation are each reviewed in an attempt to provide insight into current clinical practice and patient selection.

Management of severe tricuspid valve regurgitation due to ruptured papillary muscle in a patient with mediastinitis early after heart transplant.

Objective: Even though severe tricuspid regurgitation is not uncommon after cardiac transplantation, primary severe tricuspid regurgitation is rare. We present such a case with additional complexities. Methods: The patient was 44-year-old man with a HeartWare durable left ventricular assist device (Heartware Inc) who received a temporary right ventricular assist device (RVAD) with a ProtekDuo cannula (LivaNova Inc USA) for refractory ventricular fibrillation and underwent a heart transplant as United Network for Organ Sharing Status 1, in the presence of partially compensated cardiogenic shock, renal failure. Given complex re-operative surgery in a volume-overloaded patient with unknown pulmonary vascular resistance, an RVAD cannula was preserved and re- inserted during cardiac transplant. Postoperatively he required hemodialysis, had severe primary tricuspid regurgitation discovered after RVAD removal and developed Enterobacter mediastinitis. He underwent complex tricuspid valve repair for flail tricuspid leaflet due to ruptured papillary muscle likely due to RVAD cannula injury, after multiple mediastinal washouts and was followed by delayed chest reconstruction. Results: The patient is doing well, 6 months after discharge to home, asymptomatic, without re-admissions, on renal recovery path, with no tricuspid regurgitation and good biventricular function. Conclusions: Replacing the tricuspid valve in presence of hemodialysis catheter, immunosuppression and mediastinitis could be high risk for endocarditis. Even though we have short-term follow-up, tricuspid valve repair can be an effective way of managing primary severe regurgitation especially when there is a desire or need to avoid valve replacement.

Performance of an Irrigated Bipolar Radiofrequency Ablation Clamp on Explanted Human Hearts.

BACKGROUND: Bipolar radiofrequency (RF) clamps are commonly used during surgical ablation for atrial fibrillation (AF). This study examined the efficacy of an irrigated bipolar RF clamp to create transmural lesions in an ex vivo human heart model. METHODS: Ten donor hearts, turned down for transplantation, were explanted and arrested with cold cardioplegia. The ablations of the Cox Maze IV procedure were performed using the Cardioblate LP (Medtronic, Inc) irrigated bipolar RF clamp. In the first 5 hearts, each lesion was created with a single application of RF, whereas in the remaining 5 hearts, each lesion was created with a double application of RF without unclamping. Each lesion was cross-sectioned and stained with 2,3,5-triphenyl-tetrazolium chloride to assess ablation depth and transmurality. RESULTS: A total of 100 lesions were analyzed. In the single-ablation group, 222 of 260 sections (85%) and 37 of 50 lesions (74%) were transmural. The efficacy improved significantly in the double-ablation group, in which 348 of 359 sections (97%, P < .001) and 46 of 50 lesions (92%, P = .017) were transmural. Overall, in nontransmural lesions, the epicardial fat thickness was significantly greater (1.69 ± 0.70 mm vs 0.45 ±0.10 mm, P < .001) than the transmural lesions. CONCLUSIONS: A single ablation on human atrial tissue with an irrigated bipolar RF clamp was insufficient to reliably create transmural lesions, but a double ablation significantly increased the lesion and section transmurality. Nontransmural lesions were associated with significantly thicker layers of epicardial fat, which likely decreased tissue energy delivery due to the higher resistance of fat to current flow.

Outcomes of double-valve surgery for infective endocarditis are improving in the modern era.

BACKGROUND: The incidence of infective endocarditis (IE) is rapidly increasing. Contemporary outcomes following high-risk double valve surgery (DVS) for IE are not well described. METHODS: Between 2001 and 2021, 211 patients with IE underwent combined aortic and mitral valve surgery at a tertiary care referral center. Data from the Society of Thoracic Surgeons registry, including demographics, operative details, and outcomes, were collected. Risk factors for 30-day and 1-year-mortality were analyzed. Survival was analyzed using Kaplan-Meier and Cox proportional hazards modeling. RESULTS: The study cohort had a male preponderance (73%), with a median age of 56 years (interquartile range [IQR], 44 to 63 years). Forty-five patients (21%) had a history of intravenous (IV) drug abuse, 50 (24%) were on preoperative dialysis, and 50 (24%) had prosthetic valve endocarditis. Thirty-day and 1-year mortality were 14% (n = 30) and 30% (n = 61), respectively. On multivariable Cox regression adjusting for age, prosthetic valve endocarditis, postoperative intra-aortic balloon pump (IABP), history of dialysis (adjusted hazard ratio [aHR], 1.9; 95% confidence interval [CI], 1.3 to 2.9; P = .002) and IV drug abuse (aHR, 2.0; 95% CI, 1.1-3.5; P = .02) were predictive of decreased survival. Undergoing surgery after 2010 was predictive of improved survival (aHR, 0.5; 95% CI, 0.3 to 0.8; P = .006). These patients were more likely to undergo urgent/emergent surgery (83% vs 29%; P < .001) and less likely to have an aortic root abscess (40% vs 58%; P = .03) or to require the commando procedure (13% vs 33%; P = .002). CONCLUSIONS: In this large series evaluating outcomes of DVS for IE in the modern era, although the mortality risk remained elevated, improving outcomes may be associated with earlier surgical intervention before significant disease progression. Multidisciplinary evaluation for complex IE may be considered to better understand the optimal timing and repair strategy.

Minimally Invasive Mitral Valve Surgery With Concomitant Cox Maze Procedure Is as Effective as a Median Sternotomy With Decreased Morbidity.

OBJECTIVE: A right minithoracotomy (RMT) is a minimally invasive surgical approach that has been increasingly performed for the concomitant Cox maze IV procedure (CMP) and mitral valve surgery (MVS). Little is known regarding whether long-term rhythm and survival outcomes are affected by the RMT as compared with the traditional median sternotomy (MS) approach. METHODS: Between April 2004 and April 2021, 377 patients underwent the concomitant CMP and MVS, of whom 38% had RMT. Propensity score matching yielded 116 pairs. Freedom from atrial tachyarrhythmias (ATA) was assessed with prolonged monitoring annually for 8 years. Survival, rhythm, and perioperative outcomes were compared. RESULTS: The unmatched RMT cohort had a greater freedom from ATA recurrence at 1 year (99% vs 90%, P = 0.001) and 3 years (94% vs 86%, P = 0.045). The matched RMT cohort had longer cardiopulmonary bypass (median: 215 [199 to 253] vs 170 [136 to 198] min, P < 0.001) and aortic cross-clamp (110 [98 to 124] vs 86 [71 to 102] min, P < 0.001) times but shorter intensive care time (48 [24 to 95] vs 71 [26 to 144] h, P = 0.001) and length of stay (8 [6 to 11] vs 10 [7 to 14] h, P < 0.001). More pacemakers (18% vs 4%, P < 0.001) and postoperative transfusions (57% vs 41%, P = 0.014) occurred in the MS cohort. The 30-day mortality (P = 0.651) and 8-year survival (P = 0.072) was not significantly different between the cohorts. CONCLUSIONS: Early 1-year and 3-year freedom from ATA recurrence was better in the RMT cohort compared with the MS cohort. Despite longer operative times, the RMT cohort had shorter lengths of stay, fewer postoperative transfusions, and fewer pacemakers placed.

Delayed-enhancement cardiac magnetic resonance imaging detects disease progression in patients with mitral valve disease and atrial fibrillation.

Objectives: The mechanism by which mitral valve (MV) disease leads to atrial fibrillation (AF) remains poorly understood. Delayed-enhancement cardiac magnetic resonance imaging (DE-MRI) has been used to assess left atrial (LA) fibrosis in patients with lone AF before catheter ablation; however, few studies have used DE-MRI to assess MV-induced LA fibrosis in patients with or without AF undergoing MV surgery. Methods: Between March 2018 and September 2022, 38 subjects were enrolled; 15 age-matched controls, 14 patients with lone mitral regurgitation (MR), and 9 patients with MR and AF (MR + AF). Indexed LA volume, total LA wall, and regional LA posterior wall (LAPW) enhancement were defined by the DE-MRI. One-way analysis of variance was performed. Results: LA volume and LA enhancement were associated (r = 0.451, P = .004). LA volume differed significantly between controls (37.1 ± 10.6 mL) and patients with lone MR (71.0 ± 35.9, P = .020 and controls and patients with MR + AF (99.3 ± 47.4, P < .001). The difference in LA enhancement was significant between MR + AF (16.7 ± 9.6%) versus controls (8.3 ± 3.9%, P = .006) and MR + AF versus lone MR (8.0 ± 4.8%, P = .004). Similarly, the was significantly more LAPW enhancement in the MR + AF (17.5 ± 8.7%) versus control (9.2 ± 5.1%, P = .011) and MR + AF versus lone MR (9.8 ± 6.0%, P = .020). Conclusions: Patients with MR + AF had significantly more total and LAPW fibrosis compared with both controls and lone MR. Volume and delayed enhancement were associated, but there was no difference between MR and MR + AF.

Characterization of de novo malignancy after orthotopic heart transplantation: single-centre outcomes over 20 years.

OBJECTIVES: Malignancy is the leading cause of late mortality after orthotopic heart transplantation (OHT), and the burden of post-transplantation cancer is expected to rise in proportion to increased case volume following the 2018 heart allocation score change. In this report, we evaluated factors associated with de novo malignancy after OHT with a focus on skin and solid organ cancers. METHODS: Patients who underwent OHT at our institution between 1999 and 2018 were retrospectively reviewed (n = 488). Terminal outcomes of death and development of skin and/or solid organ malignancy were assessed as competing risks. Fine-Gray subdistribution hazards regression was used to evaluate the association between perioperative patient and donor characteristics and late-term malignancy outcomes. RESULTS: By 1, 5 and 10 years, an estimated 2%, 17% and 27% of patients developed skin malignancy, while 1%, 5% and 12% of patients developed solid organ malignancy. On multivariable Fine-Gray regression, age [1.05 (1.03-1.08); P < 0.001], government payer insurance [1.77 (1.20-2.59); P = 0.006], family history of malignancy [1.66 (1.15-2.38); P = 0.007] and metformin use [1.73 (1.15-2.59); P = 0.008] were associated with increased risk of melanoma and basal or squamous cell carcinoma. Age [1.08 (1.04-1.12); P < 0.001] and family history of malignancy [2.55 (1.43-4.56); P = 0.002] were associated with an increased risk of solid organ cancer, most commonly prostate and lung cancer. CONCLUSIONS: Vigilant cancer and immunosuppression surveillance is warranted in OHT recipients at late-term follow-up. The cumulative incidence of skin and solid organ malignancies increases temporally after transplantation, and key risk factors for the development of post-OHT malignancy warrant identification and routine monitoring.

An experimental model of chronic severe mitral regurgitation.

Objective: To develop a minimally invasive, reproducible model of chronic severe mitral regurgitation (MR) that replicates the clinical phenotype of left atrial (LA) and left ventricular dilation and susceptibility to atrial fibrillation. Methods: Under transesophageal echocardiographic guidance, chordae tendinae were avulsed using endovascular forceps until the ratio of regurgitant jet area to LA area was ≥70%. Animals survived for an average of 8.6 ± 1.6 months (standard deviation) and imaged with monthly transthoracic echocardiography (TTE). Animals underwent baseline and preterminal magnetic resonance imaging. Terminal studies included TTE, transesophageal echocardiography, and rapid atrial pacing to test inducibility of atrial tachyarrhythmias. Results: Eight dogs underwent creation of severe MR and interval monitoring. Two were excluded-one died from acute heart failure, and the other had resolution of MR. Six dogs underwent the full experimental protocol; only one required medical management of clinical heart failure. MR remained severe over time, with a mean terminal regurgitant jet area to LA area of 71 ± 14% (standard deviation) and regurgitant fraction of 52 ± 11%. Mean LA volume increased over 130% (TTE: 163 ± 147%, P = .039; magnetic resonance imaging: 132 ± 54%, P = .011). Mean left ventricular end-diastolic volume increased by 38 ± 21% (P = .008). Inducible atrial tachyarrhythmias were seen in 4 of 6 animals at terminal surgery, and none at baseline. Conclusions: Within the 6 dogs that successfully completed the full experimental protocol, this model replicated the clinical phenotype of severe MR, which led to marked structural and electrophysiologic cardiac remodeling. This model allowed for precise measurements at repeated time points and will facilitate future studies to elucidate the mechanisms of atrial and ventricular remodeling secondary to MR and the pathophysiology of valvular atrial fibrillation.

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).