Michael Reardon - Academia.edu (original) (raw)

Papers by Michael Reardon

Journal of the American College of Cardiology

Journal of the American College of Cardiology

Journal of the American College of Cardiology, 2020

Background: There are limited data to inform a minimum institutional mitral valve (MV) procedure ... more Background: There are limited data to inform a minimum institutional mitral valve (MV) procedure volume to start a transcatheter MV repair (TMVr) program. The goal of this analysis is to examine the relationship between institutional MV repair volumes and outcomes in Medicare patients. Methods: We used the 2017 100% Medicare Standard Analytic File to assess 1) surgical MV repair (SMVr) volumes and outcomes, and 2) SMVr/TMVr volumes and TMVr outcomes. Hospitals were classified based on annual SMVr volume [low (1-24), medium (25-39), high (40+)] or TMVr volume [low (1-18), medium (19-51), high (52+)] using Definitive Healthcare data. In-hospital mortality and 6-month post-discharge outcomes (mortality, cardiovascular rehospitalizations) were analyzed using generalized estimating equations and Cox proportional hazard models, respectively. All models were risk adjusted using a propensity score based on both patient (age, sex, race, region, Elixhauser comorbidity score) and hospital (bed size, teaching status, region) characteristics. Results: This analysis confirmed the known relationship between SMVr volume and in-hospital mortality but did not find statistically significant relationships between either SMVr or TMVr volume and TMVr outcomes. Conclusion: TMVr outcomes for Medicare patients did not vary significantly by SMVr or TMVr institutional volume. These findings do not support the use of SMVr volume as a criterion for establishing new TMVr programs.

Journal of the American College of Cardiology, 2018

BACKGROUND There is inadequate evidence on modifiable risk factors for stroke to guide effective ... more BACKGROUND There is inadequate evidence on modifiable risk factors for stroke to guide effective stroke prevention for patients undergoing transcatheter aortic valve replacement (TAVR). This study was conducted to identify those factors. METHODS This is a retrospective case-control study using a prospectively collected dataset at a single high-volume transcatheter aortic valve replacement (TAVR) quaternary academic medical center in Houston, Texas, USA, from 11/8/11-3/28/18. In hospital stroke post-TAVR was assessed by penalized logistic regression, guided by locally weighted scatterplot smoothing (LOWESS) regression and machine learning-driven backward propagation neural networks. RESULTS 1654 unique subjects underwent 1,658 TAVR procedures. The in-hospital stroke rate was 2.29% (38), the average length of stay was 7.01 days (SD 8.28), and mortality rate was 2.71% (45). Even adjusting for confounders (prior stroke and atrial fibrillation, LVEF, pre-op creatinine >2 mg/dL, TAVR generation, and procedure year), albumin <2.5 g/dL significantly increased stroke odds (OR 2.26, 95%CI 1.05-4.85; p¼0.036). This model performed similarly to the machine learning neural network (accuracy and RMSE 97.55% and 0.154 versus 97.59% and 0.155). CONCLUSION This is the first known analysis to demonstrate a modifiable factor such as albumin threshold that can significantly and independently increase post-TAVR stroke odds. Additional studies are required to determine the impact of pre-TAVR interventions to even further reduce the already small peri-procedure complication rate.

Seminars in Thoracic and Cardiovascular Surgery, 2015

Introduction: Minimally invasive mitral valve (MV) surgery, often requiring femoral artery (FA) c... more Introduction: Minimally invasive mitral valve (MV) surgery, often requiring femoral artery (FA) cannulation, is increasingly being adopted. There is concern about increased stroke rates associated with minimally invasive MV surgery. This study aims to examine whether FA cannulation is independently associated with increased stroke rates in minimally invasive MV procedures. Methods: Mitral valve procedures from January 2004 to June 2012 were reviewed using our institutional Society of Thoracic Surgeons database. Included were 384 patients, after the exclusion of patients with emergency procedures, infective endocarditis, other concomitant procedures, patients > 60 years and those with non-standard aortic clamping (endo-balloon or no clamp). Patients were divided into 2 groups; aortic (n=327) and femoral (n=57) cannulation. Risk adjustments through multivariable regression were used to identify independent predictors for various outcomes. Adjustments were made for cardiopulmonary bypass (CPB) and aortic clamp times. Results: Preoperatively, the femoral cannulation group had less baseline cerebrovascular disease (p=0.032), heart failure (p=0.028) and atrial fibrillation (p=0.012). Other baseline characteristics were similar. Aortic cannulation group had shorter CPB (p< 0.001) and clamp times (p< 0.001). There were more repairs done in the FA cannulation group as opposed to replacements. Risk-adjusted outcomes showed a higher incidence of permanent stroke in the femoral cannulation group (p=0.032). Other outcomes were not significantly different. Conclusion: Femoral artery cannulation may be associated with increased stroke rates in isolated mitral valve surgery. Antegrade arterial cannulation (direct aortic or axillary cannulation) may be preferable in minimally invasive mitral valve procedures. Randomized trial data is needed.

The Journal of invasive cardiology, 2015

Dynamic left ventricular outflow tract obstruction and left ventricular mid-cavity obliteration a... more Dynamic left ventricular outflow tract obstruction and left ventricular mid-cavity obliteration are phenomena that can complicate the postoperative course in patients who undergo surgical aortic valve replacement for aortic stenosis, and may be markers of increased morbidity and mortality. Recently, reports describing dynamic intraventricular obstruction following transcatheter aortic valve replacement (TAVR) have emerged. We report a case of dynamic left ventricular mid-cavity obstruction due to disordered atrioventricular synchrony immediately following TAVR, and its reversal with restoration of atrioventricular synchrony. This case highlights the essential role of atrial contraction in the management of this phenomenon.

Journal of the American College of Cardiology, 2013

Background: Prediction of an optimal C-arm angle that aligns the coronary sinuses for valve deplo... more Background: Prediction of an optimal C-arm angle that aligns the coronary sinuses for valve deployment is critical during TAVR. Current solutions derive the deployment angle from multiple angiograms, reconstruction of multi-slice CT (MSCT) or C-arm CT rotational angiography (CTRA). We evaluated a method based on co-registration of MSCT and CTRA to predict deployment angle without using additional contrast agent. methods: Non-contrast CTRA (syngo DynaCT®) was acquired using a 5-sec protocol, with breath-hold and rapid-pacing. Aortic root calcifications from CTRA and MSCT were segmented and aligned with a semi-automatic rigid image registration algorithm. Optimal deployment angle was derived using prototype software (Siemens AG, Germany). This approach also accounted for differences in patient positioning. To evaluate the adequacy of the predicted angle, we compared the number of planning aortic root angiograms before and after adopting our co-registration approach. results: From Oct 2011 to Oct 1012, 10 patients underwent TAVR using predicted angle from MSCT alone, and 24 patients using co-registration. 7/10 pts (70%) in MSCT group required >2 angiograms before prosthesis insertion, compared to 3/24 pts (12.5%) in the co-registered group. conclusion: We propose a method to predict optimal C-arm angle for valve deployment based on MSCT-CTRA (non-contrast) co-registration. Such image registration strategies can potentially help in limiting contrast usage.

Journal of Medical Economics, 2013

The Journal of Heart and Lung Transplantation, 2010

Characterization of a cardiac mass using a systematic multimodality imaging approach To the Edito... more Characterization of a cardiac mass using a systematic multimodality imaging approach To the Editor: This report highlighted a multimodality imaging approach for the characterization of cardiac masses. Initial identification of a left ventricle mass was made with 2D transthoracic echocardiogram (TTE). Real-time 3D TTE added further anatomic localization and indicated that the mass was attached to the posterior mitral valve leaflet/ annulus complex, not to ventricular myocardium. Tissue characterization was performed with cardiac magnetic resonance (CMR) to refine the differential diagnosis to that of a myxoma. 1 Unique features included a large myxoma originating from the ventricular side of the mitral valve, CMR for tissue characterization and cardiac auto-transplantation 2 with complete ex vivo tumor resection, and implantation of a mechanical mitral valve prosthesis. Figures 1 & 2.

The Journal of Thoracic and Cardiovascular Surgery

The Journal of Thoracic and Cardiovascular Surgery

JTCVS Open, 2022

Disclosures: Dr Reardon served on the executive committee of all the Medtronic randomized trials ... more Disclosures: Dr Reardon served on the executive committee of all the Medtronic randomized trials and as national surgical principal investigator for SURTAVI and Evolut Low Risk trials. He is a consultant to Medtronic, Boston Scientific, Abbott Medical, and Gore Medical. Dr Faza reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.

JTCVS Techniques, 2021

Open thoracoabdominal aortic aneurysm repair has been one of the most demanding operations perfor... more Open thoracoabdominal aortic aneurysm repair has been one of the most demanding operations performed, both for the surgeon and the patient, since its original description by Etheridge and colleagues in 1955 and popularized at our institution by Crawford and colleagues in the 1960s. Over the years, multiple variations in the steps of the operation and various adjuncts have been proposed to improve on the results and minimize the complications associated with these complex procedures. Perfusion adjuncts to avoid cardiopulmonary bypass and pump dose systemic heparinization have included the Gott shunt, in-line mesenteric shunting as described by Cambria and colleagues, and partial left heart bypass. The technique of “clamp and sew” for Crawford extent 1, 2, and 3 thoracoabdominal aortic aneurysm has for the most part been abandoned owing to the increased risk of spinal cord ischemia and visceral malperfusion. In the current era of open thoracoabdominal aortic aneurysm repair, widely pe...

The Journal of Thoracic and Cardiovascular Surgery, 2021

Alternative access without chest wall penetration provides a reasonable substitute for transfemor... more Alternative access without chest wall penetration provides a reasonable substitute for transfemoral access TAVR.

The Journal of Thoracic and Cardiovascular Surgery, 2021

Midterm survival after TAVR is lower in high-and intermediaterisk patients who have a severe peri... more Midterm survival after TAVR is lower in high-and intermediaterisk patients who have a severe perioperative stroke. The impact of complications on outcomes in low-risk patients requires more study.

Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery, 2021

Objective There is an increasing amount of evidence supporting use of transcatheter aortic valve ... more Objective There is an increasing amount of evidence supporting use of transcatheter aortic valve replacement (TAVR) for treatment of aortic stenosis in patients at low or intermediate risk for surgical aortic valve replacement (SAVR). TAVR is now approved for use in all patient cohorts. Despite this, there remains debate about the relative efficacy of TAVR compared with SAVR in lower-risk cohorts and various subgroups of patients. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) and propensity-matched trials to guide a consensus among expert cardiologists and surgeons. Methods Studies comparing TAVR and SAVR in low- and intermediate-risk patients were identified by a thorough search of the major databases. Mortality, stroke, and other perioperative outcomes were assessed at 30 days and 1 year. Results Early mortality was lower in TAVR compared to SAVR in RCTs, but not propensity-matched studies in low-risk cohorts (0.66% vs 1.5%; odds ratio [...

JTCVS Techniques, 2020

Esophageal left atrial fistula is a rare but potentially lethal complication of left atrial ablat... more Esophageal left atrial fistula is a rare but potentially lethal complication of left atrial ablation. Early recognition, appropriate planning, and surgery are imperative for survival.

Journal of the American College of Cardiology

Journal of the American College of Cardiology

Journal of the American College of Cardiology, 2020

Background: There are limited data to inform a minimum institutional mitral valve (MV) procedure ... more Background: There are limited data to inform a minimum institutional mitral valve (MV) procedure volume to start a transcatheter MV repair (TMVr) program. The goal of this analysis is to examine the relationship between institutional MV repair volumes and outcomes in Medicare patients. Methods: We used the 2017 100% Medicare Standard Analytic File to assess 1) surgical MV repair (SMVr) volumes and outcomes, and 2) SMVr/TMVr volumes and TMVr outcomes. Hospitals were classified based on annual SMVr volume [low (1-24), medium (25-39), high (40+)] or TMVr volume [low (1-18), medium (19-51), high (52+)] using Definitive Healthcare data. In-hospital mortality and 6-month post-discharge outcomes (mortality, cardiovascular rehospitalizations) were analyzed using generalized estimating equations and Cox proportional hazard models, respectively. All models were risk adjusted using a propensity score based on both patient (age, sex, race, region, Elixhauser comorbidity score) and hospital (bed size, teaching status, region) characteristics. Results: This analysis confirmed the known relationship between SMVr volume and in-hospital mortality but did not find statistically significant relationships between either SMVr or TMVr volume and TMVr outcomes. Conclusion: TMVr outcomes for Medicare patients did not vary significantly by SMVr or TMVr institutional volume. These findings do not support the use of SMVr volume as a criterion for establishing new TMVr programs.

Journal of the American College of Cardiology, 2018

BACKGROUND There is inadequate evidence on modifiable risk factors for stroke to guide effective ... more BACKGROUND There is inadequate evidence on modifiable risk factors for stroke to guide effective stroke prevention for patients undergoing transcatheter aortic valve replacement (TAVR). This study was conducted to identify those factors. METHODS This is a retrospective case-control study using a prospectively collected dataset at a single high-volume transcatheter aortic valve replacement (TAVR) quaternary academic medical center in Houston, Texas, USA, from 11/8/11-3/28/18. In hospital stroke post-TAVR was assessed by penalized logistic regression, guided by locally weighted scatterplot smoothing (LOWESS) regression and machine learning-driven backward propagation neural networks. RESULTS 1654 unique subjects underwent 1,658 TAVR procedures. The in-hospital stroke rate was 2.29% (38), the average length of stay was 7.01 days (SD 8.28), and mortality rate was 2.71% (45). Even adjusting for confounders (prior stroke and atrial fibrillation, LVEF, pre-op creatinine >2 mg/dL, TAVR generation, and procedure year), albumin <2.5 g/dL significantly increased stroke odds (OR 2.26, 95%CI 1.05-4.85; p¼0.036). This model performed similarly to the machine learning neural network (accuracy and RMSE 97.55% and 0.154 versus 97.59% and 0.155). CONCLUSION This is the first known analysis to demonstrate a modifiable factor such as albumin threshold that can significantly and independently increase post-TAVR stroke odds. Additional studies are required to determine the impact of pre-TAVR interventions to even further reduce the already small peri-procedure complication rate.

Seminars in Thoracic and Cardiovascular Surgery, 2015

Introduction: Minimally invasive mitral valve (MV) surgery, often requiring femoral artery (FA) c... more Introduction: Minimally invasive mitral valve (MV) surgery, often requiring femoral artery (FA) cannulation, is increasingly being adopted. There is concern about increased stroke rates associated with minimally invasive MV surgery. This study aims to examine whether FA cannulation is independently associated with increased stroke rates in minimally invasive MV procedures. Methods: Mitral valve procedures from January 2004 to June 2012 were reviewed using our institutional Society of Thoracic Surgeons database. Included were 384 patients, after the exclusion of patients with emergency procedures, infective endocarditis, other concomitant procedures, patients > 60 years and those with non-standard aortic clamping (endo-balloon or no clamp). Patients were divided into 2 groups; aortic (n=327) and femoral (n=57) cannulation. Risk adjustments through multivariable regression were used to identify independent predictors for various outcomes. Adjustments were made for cardiopulmonary bypass (CPB) and aortic clamp times. Results: Preoperatively, the femoral cannulation group had less baseline cerebrovascular disease (p=0.032), heart failure (p=0.028) and atrial fibrillation (p=0.012). Other baseline characteristics were similar. Aortic cannulation group had shorter CPB (p< 0.001) and clamp times (p< 0.001). There were more repairs done in the FA cannulation group as opposed to replacements. Risk-adjusted outcomes showed a higher incidence of permanent stroke in the femoral cannulation group (p=0.032). Other outcomes were not significantly different. Conclusion: Femoral artery cannulation may be associated with increased stroke rates in isolated mitral valve surgery. Antegrade arterial cannulation (direct aortic or axillary cannulation) may be preferable in minimally invasive mitral valve procedures. Randomized trial data is needed.

The Journal of invasive cardiology, 2015

Dynamic left ventricular outflow tract obstruction and left ventricular mid-cavity obliteration a... more Dynamic left ventricular outflow tract obstruction and left ventricular mid-cavity obliteration are phenomena that can complicate the postoperative course in patients who undergo surgical aortic valve replacement for aortic stenosis, and may be markers of increased morbidity and mortality. Recently, reports describing dynamic intraventricular obstruction following transcatheter aortic valve replacement (TAVR) have emerged. We report a case of dynamic left ventricular mid-cavity obstruction due to disordered atrioventricular synchrony immediately following TAVR, and its reversal with restoration of atrioventricular synchrony. This case highlights the essential role of atrial contraction in the management of this phenomenon.

Journal of the American College of Cardiology, 2013

Background: Prediction of an optimal C-arm angle that aligns the coronary sinuses for valve deplo... more Background: Prediction of an optimal C-arm angle that aligns the coronary sinuses for valve deployment is critical during TAVR. Current solutions derive the deployment angle from multiple angiograms, reconstruction of multi-slice CT (MSCT) or C-arm CT rotational angiography (CTRA). We evaluated a method based on co-registration of MSCT and CTRA to predict deployment angle without using additional contrast agent. methods: Non-contrast CTRA (syngo DynaCT®) was acquired using a 5-sec protocol, with breath-hold and rapid-pacing. Aortic root calcifications from CTRA and MSCT were segmented and aligned with a semi-automatic rigid image registration algorithm. Optimal deployment angle was derived using prototype software (Siemens AG, Germany). This approach also accounted for differences in patient positioning. To evaluate the adequacy of the predicted angle, we compared the number of planning aortic root angiograms before and after adopting our co-registration approach. results: From Oct 2011 to Oct 1012, 10 patients underwent TAVR using predicted angle from MSCT alone, and 24 patients using co-registration. 7/10 pts (70%) in MSCT group required >2 angiograms before prosthesis insertion, compared to 3/24 pts (12.5%) in the co-registered group. conclusion: We propose a method to predict optimal C-arm angle for valve deployment based on MSCT-CTRA (non-contrast) co-registration. Such image registration strategies can potentially help in limiting contrast usage.

Journal of Medical Economics, 2013

The Journal of Heart and Lung Transplantation, 2010

Characterization of a cardiac mass using a systematic multimodality imaging approach To the Edito... more Characterization of a cardiac mass using a systematic multimodality imaging approach To the Editor: This report highlighted a multimodality imaging approach for the characterization of cardiac masses. Initial identification of a left ventricle mass was made with 2D transthoracic echocardiogram (TTE). Real-time 3D TTE added further anatomic localization and indicated that the mass was attached to the posterior mitral valve leaflet/ annulus complex, not to ventricular myocardium. Tissue characterization was performed with cardiac magnetic resonance (CMR) to refine the differential diagnosis to that of a myxoma. 1 Unique features included a large myxoma originating from the ventricular side of the mitral valve, CMR for tissue characterization and cardiac auto-transplantation 2 with complete ex vivo tumor resection, and implantation of a mechanical mitral valve prosthesis. Figures 1 & 2.

The Journal of Thoracic and Cardiovascular Surgery

The Journal of Thoracic and Cardiovascular Surgery

JTCVS Open, 2022

Disclosures: Dr Reardon served on the executive committee of all the Medtronic randomized trials ... more Disclosures: Dr Reardon served on the executive committee of all the Medtronic randomized trials and as national surgical principal investigator for SURTAVI and Evolut Low Risk trials. He is a consultant to Medtronic, Boston Scientific, Abbott Medical, and Gore Medical. Dr Faza reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.

JTCVS Techniques, 2021

Open thoracoabdominal aortic aneurysm repair has been one of the most demanding operations perfor... more Open thoracoabdominal aortic aneurysm repair has been one of the most demanding operations performed, both for the surgeon and the patient, since its original description by Etheridge and colleagues in 1955 and popularized at our institution by Crawford and colleagues in the 1960s. Over the years, multiple variations in the steps of the operation and various adjuncts have been proposed to improve on the results and minimize the complications associated with these complex procedures. Perfusion adjuncts to avoid cardiopulmonary bypass and pump dose systemic heparinization have included the Gott shunt, in-line mesenteric shunting as described by Cambria and colleagues, and partial left heart bypass. The technique of “clamp and sew” for Crawford extent 1, 2, and 3 thoracoabdominal aortic aneurysm has for the most part been abandoned owing to the increased risk of spinal cord ischemia and visceral malperfusion. In the current era of open thoracoabdominal aortic aneurysm repair, widely pe...

The Journal of Thoracic and Cardiovascular Surgery, 2021

Alternative access without chest wall penetration provides a reasonable substitute for transfemor... more Alternative access without chest wall penetration provides a reasonable substitute for transfemoral access TAVR.

The Journal of Thoracic and Cardiovascular Surgery, 2021

Midterm survival after TAVR is lower in high-and intermediaterisk patients who have a severe peri... more Midterm survival after TAVR is lower in high-and intermediaterisk patients who have a severe perioperative stroke. The impact of complications on outcomes in low-risk patients requires more study.

Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery, 2021

Objective There is an increasing amount of evidence supporting use of transcatheter aortic valve ... more Objective There is an increasing amount of evidence supporting use of transcatheter aortic valve replacement (TAVR) for treatment of aortic stenosis in patients at low or intermediate risk for surgical aortic valve replacement (SAVR). TAVR is now approved for use in all patient cohorts. Despite this, there remains debate about the relative efficacy of TAVR compared with SAVR in lower-risk cohorts and various subgroups of patients. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) and propensity-matched trials to guide a consensus among expert cardiologists and surgeons. Methods Studies comparing TAVR and SAVR in low- and intermediate-risk patients were identified by a thorough search of the major databases. Mortality, stroke, and other perioperative outcomes were assessed at 30 days and 1 year. Results Early mortality was lower in TAVR compared to SAVR in RCTs, but not propensity-matched studies in low-risk cohorts (0.66% vs 1.5%; odds ratio [...

JTCVS Techniques, 2020

Esophageal left atrial fistula is a rare but potentially lethal complication of left atrial ablat... more Esophageal left atrial fistula is a rare but potentially lethal complication of left atrial ablation. Early recognition, appropriate planning, and surgery are imperative for survival.