Expert Opinions on the Debate of Pericardial Reconstruction in Cardiovascular Surgery: To Close or Not to Close?

BACKGROUND: As of 2019, pericardial closure was performed in only a small portion of the over 320,000 cardiac surgeries performed annually. However, evidence regarding the benefits of pericardial closure or reconstruction has been accruing, particularly with the publication of the RECON study in 2019.  Methods: This group of authors convened to try to arrive at consensus expert opinion regarding pericardial reconstruction. Structured topic questions initially were used to stimulate discussion. Subsequently, a survey of proposed expert opinion statements was conducted among the authors. Based on that survey, consensus expert opinion statements and recommendations were compiled. RESULTS: The expert opinions encompass various topics relating to pericardial reconstruction, including definitions, benefits/risks, and technique. Observed benefits include reductions in: (1) adhesions; (2) postoperative pericardial effusion, atrial fibrillation, and bleeding; and (3) readmissions and length of hospital stay. Expert opinion recommendations regarding surgical technique are compiled into a single chart. Complete pericardial reconstruction should be performed, using native pericardial tissue if available and viable; if not feasible, a patch may be used. Patches that stimulate the formation of site-specific tissue in situ (such as natural extracellular matrix) may have additional benefits (including bioregenerative properties and lack of inflammatory response). Closure should be taut, but tension-free. Adequate drainage of the closed pericardium must be ensured. CONCLUSIONS: Based on available data and collective surgical experience, we endorse pericardial reconstruction as standard approach in appropriately selected patients. We also endorse adoption of standardized pericardial reconstruction techniques to optimize patient outcomes and improve evidence quality in future studies.

Complex electrophysiological remodeling in postinfarction ischemic heart failure.

Heart failure (HF) following myocardial infarction (MI) is associated with high incidence of cardiac arrhythmias. Development of therapeutic strategy requires detailed understanding of electrophysiological remodeling. However, changes of ionic currents in ischemic HF remain incompletely understood, especially in translational large-animal models. Here, we systematically measure the major ionic currents in ventricular myocytes from the infarct border and remote zones in a porcine model of post-MI HF. We recorded eight ionic currents during the cell's action potential (AP) under physiologically relevant conditions using selfAP-clamp sequential dissection. Compared with healthy controls, HF-remote zone myocytes exhibited increased late Na+ current, Ca2+-activated K+ current, Ca2+-activated Cl- current, decreased rapid delayed rectifier K+ current, and altered Na+/Ca2+ exchange current profile. In HF-border zone myocytes, the above changes also occurred but with additional decrease of L-type Ca2+ current, decrease of inward rectifier K+ current, and Ca2+ release-dependent delayed after-depolarizations. Our data reveal that the changes in any individual current are relatively small, but the integrated impacts shift the balance between the inward and outward currents to shorten AP in the border zone but prolong AP in the remote zone. This differential remodeling in post-MI HF increases the inhomogeneity of AP repolarization, which may enhance the arrhythmogenic substrate. Our comprehensive findings provide a mechanistic framework for understanding why single-channel blockers may fail to suppress arrhythmias, and highlight the need to consider the rich tableau and integration of many ionic currents in designing therapeutic strategies for treating arrhythmias in HF.

Postoperative Acute Kidney Injury and Blood Product Transfusion After Synthetic Colloid Use During Cardiac Surgery.

OBJECTIVES: This study assessed the effect of 2 types of hydroxyethyl starches (HES) on renal integrity and blood transfusion in cardiac surgery patients. DESIGN: Retrospective investigation. SETTING: Patients from a single tertiary medical center. PARTICIPANTS: Inclusion criteria included coronary artery bypass graft (CABG) and/or valve surgery that included cardiopulmonary bypass with aortic cross-clamping. INTERVENTIONS: Intraoperative HES and blood product administration. MEASUREMENTS AND MAIN RESULTS: The study comprised 1,265 patients who met inclusion criteria. Of these patients, 70% received HES, and of these, 47% received<1,000 mL and 53% received≥1,000 mL. There was no difference in the development of acute kidney injury between the 2 groups. A parsimonious propensity model for colloids showed that combined CABG and valve surgery were less likely to be associated with HES administration than was CABG alone (OR 0.68, confidence interval [CI] 0.46-0.97; p = 0.04). Intra-aortic balloon pump use was less likely to be associated with HES administration (OR 0.57, CI 0.38-0.86; p = 0.007). Patients with chronic kidney disease, stages 3 to 5, were less likely to receive HES, with an OR of 0.56 (CI 0.38-0.84; p = 0.004); 0.51 (CI 0.20-1.33; p = 0.170); and 0.23 (CI 0.12-0.44; p<0.0001), respectively, for each stage. No difference was noted in red blood cell transfusion. However, fresh frozen plasma, cryoprecipitate, and platelet transfusions were significantly higher with larger volumes of HES, with an OR of 2.03 (CI 1.64-2.52; p<0.001); 1.60 (CI 1.30-1.97; p<0.000); and 1.62 (CI 1.21-2.15; p = 0.006), respectively. No differences in surgical mortality were found between the colloid and noncolloid groups. CONCLUSIONS: This study showed no association of postoperative acute kidney injury and red blood cell transfusion between the colloid and noncolloid groups. Although the complication rate was higher with HES administration, there was no difference in surgery mortality between the 2 groups.

Pericardial reconstruction using an extracellular matrix implant correlates with reduced risk of postoperative atrial fibrillation in coronary artery bypass surgery patients.

BACKGROUND: Postoperative atrial fibrillation (AF) is a significant complication following open heart surgery, with potentially serious clinical and economic implications. To assess the effect of a novel procedure, pericardial reconstruction using a porcine-derived extracellular matrix (ECM) implant, on the risk of postoperative AF after primary isolated coronary artery bypass grafting (CABG), we performed a retrospective comparison of the incidence of postoperative AF in patients who underwent this procedure versus an untreated control group. METHODS: We performed a retrospective comparison of the incidence of postoperative AF in 111 patients who underwent a pericardial reconstruction procedure with the CorMatrix ECM for Pericardial Closure (CorMatrix Cardiovascular, Atlanta, GA, USA) following primary isolated CABG, versus a control group of 111 patients who did not undergo pericardial reconstruction. RESULTS: Postoperative AF occurred in 43 of 111 control patients (39%; lower control limit [LCL], 30%; upper control limit [UCL], 49%) but in only 20 of 111 treated patients (18%; LCL, 11%; UCL, 27%). This result represents a 54% reduction in relative risk in the treatment group (P < .001). There was a small but statistically insignificant decrease in the hospital length of stay for the treated patients. The 2 treatment groups exhibited similar postoperative complication profiles. CONCLUSIONS: In this retrospective study, pericardial reconstruction with the ECM implant contributed directly to a statistically significant and clinically meaningful reduction in the rate of postoperative AF in patients undergoing primary isolated CABG. A prospective multicenter randomized trial has been planned to further test this approach.

Minimally invasive surgical management of penetrating chest injury from kinetic impact bean bag projectile.

Bean bag guns are considered "non-lethal" weapons used by law enforcement. There are emerging reports in the medical literature on management of penetrating, intrathoracic injuries and none were found that involve potential cardiac complications. We present a case of a penetrating bean bag involving the pericardium. A young, adult man was shot in the left axillary region by law enforcement and presented hemodynamically stable. Computed Tomography (CT) demonstrated a bean bag anterolateral to the pericardium, associated with a small pulmonary contusion and hemopneumothorax. He underwent a left tube thoracostomy and sub-xiphoid pericardial window with cardiopulmonary bypass on standby. The diagnostic pericardial window showed no pericardial effusion and the foreign body extraction was successfully performed through the subxiphoid incision via Video Assisted Thoracoscopic Surgery. There were no intra-operative or post-operative complications.

Division of the brachioradialis muscle: a modification of the current technique in endoscopic radial artery harvesting.

BACKGROUND: Utilization of the radial artery as a conduit for coronary artery bypass grafting has increased significantly over the past 8 years. Concurrently, minimally invasive surgical techniques have been increasingly applied resulting in improved aesthetics, less pain, and decreased morbidity and length of hospital stay. Endoscopic radial artery harvesting (ERAH) has been shown to be of benefit to patients undergoing coronary artery bypass grafting. The brachioradialis is a recognized limitation in ERAH. To date, the standard operative techniques for ERAH have included maintaining the integrity of the brachioradialis muscle. Objective. The aim of this study was to assess the effect of dividing the medial border of the brachioradialis muscle during ERAH. METHODS: We performed ERAH on 9 cadaveric arms using standard endoscopic vein harvesting equipment (30-degree/5-mm endoscope, subcutaneous retractor, and pig-tail vessel dissector) and ultrasonic harmonic coagulating shears. In 5 cadaveric arms, the medial aspect of the brachioradialis muscle was preserved during the dissection. In 4 arms, the medial border of the brachioradialis muscle was divided. All 9 harvests were timed and compared. At the completion of the endoscopic dissection, all 9 arms were opened and examined for neurovascular injury. RESULTS: In cadaveric arms, modifying the current ERAH technique by dividing the medial border of the brachioradialis muscle resulted in a visible increase in tunnel size. In the group where the brachioradialis muscle was divided, a statistically significant reduction in harvest time of 32% was observed (P = .02). Post-harvest examination revealed no gross neurovascular injury; specifically, no injuries to the superficial branches of the radial nerve or the lateral antebrachial cutaneous nerves were identified. CONCLUSION: Division of the medial border of the brachioradialis muscle during endoscopic radial artery harvesting appears to be a safe technique modification that subjectively improves working space and vision of vital structures, facilitating ease of the procedure. Objectively, division of the medial border of the brachioradialis muscle resulted in a statistically significant reduction in harvest time in cadaveric arms when compared with the current technique of ERAH. A clinical pilot study to verify the efficacy and safety of this technique modification is warranted.

Small intestinal submucosa-derived extracellular matrix bioscaffold significantly enhances angiogenic factor secretion from human mesenchymal stromal cells.

INTRODUCTION: The in vivo therapeutic effect of mesenchymal stromal cells (MSCs) is currently believed to be tightly linked to their paracrine secretion ability. However, insufficient or imprecise cell delivery, low cell survival and retention post-transplant, along with harsh donor site microenvironments, are major barriers to the clinical success of MSC therapies. Here we tested a small intestinal submucosa (SIS)-derived extracellular matrix (ECM) bioscaffold augmented with MSCs, with the hypothesis that they will facilitate the precise delivery of increased numbers of MSCs therefore improving cell viability and retention. METHODS: In this study, we evaluated the secretion of angiogenic factors from three human MSC lines cultured on SIS ECM. We used human antibody array and enzyme-linked immunosorbent assay to measure the level of angiogenic factors released from MSCs when cultured on SIS ECM or regular tissue culture plastic. We tested MSCs cultured for three different time points. RESULTS: We found that the SIS ECM culture environment can significantly enhance the release of several angiogenic factors when compared to MSCs cultured on standard tissue culture plastic. Specifically, vascular endothelial growth factor and interleukin-8 secretion was significantly increased at 24, 48 and 72 hours postseeding onto SIS ECM whereas vascular endothelial growth factor release for cells cultured on plastic surface remained the same during these time points. We also observed significant donor to donor variation in cytokine production. CONCLUSIONS: This study demonstrates that MSCs transplanted onto a SIS ECM may greatly increase their therapeutic potential through an increase in pro-angiogenic cytokine release.

Hybrid robotic coronary artery surgery and angioplasty in multivessel coronary artery disease.

BACKGROUND: Complete surgical revascularization that includes left internal thoracic artery grafting to the left anterior descending coronary artery remains the gold standard of treatment for coronary artery disease. Not all patients are good candidates for sternotomy. Therefore, we sought to identify a strategy that would combine the long-term advantages of internal thoracic artery grafting to lessen surgical trauma while still allowing complete revascularization. METHODS: A total of 54 consecutive patients from four institutions underwent hybrid revascularization combining surgery and angioplasty. All internal thoracic artery grafts were endoscopically harvested with robotic assistance using either the Aesop or Zeus system, and all anastomoses were manually constructed through a 4- to 6-cm anterior thoracotomy incision. Angioplasty was carried out to achieve total revascularization to ungrafted vessels. RESULTS: There were no early or late deaths, myocardial infarctions, strokes, or wound infections. Of the patients, 37 (69%) were extubated in the operating room. Length of stay in the intensive care unit averaged 24.4 hours and hospital stay 3.45 days. In all, 16 patients (29.6%) required transfusion of packed red blood cells. Late complications included 1 patient with stent occlusion at 3 months and 2 patients with in-stent restenosis. Three patients were treated for postpericardiotomy syndrome. Mean follow-up was 11.7 months. Event-free was survival 87.1% and freedom from recurrent angina 98.3%. CONCLUSIONS: Hybrid endoscopic atraumatic internal thoracic artery to anterior descending coronary artery graft surgery combined with angioplasty is a reasonable revascularization strategy in multiple vessel coronary artery disease in selected patients. Longer follow-up and more patient data in a randomized study are needed to determine the patient cohort most likely to benefit from this approach.

Analysis of the learning curve in telerobotic, beating heart coronary artery bypass grafting: a 90 patient experience.

BACKGROUND: Recent articles have commented on the "learning curve" in robotic-assisted coronary artery bypass grafting. We systematically studied this phenomenon using standard statistical and cumulative sum (CUSUM) failure methods. METHODS: Ninety patients underwent internal thoracic artery (ITA) takedown and an attempt at ITA to coronary bypass on the beating heart using the Zeus telerobotic system from September 1999 to December 2001. The rates of mortality and 11 predefined major complications were compared in five quintiles of 18 consecutive patients each and a CUSUM curve was generated for the entire cohort. RESULTS: All patients but one underwent successful endoscopic ITA takedown. Thirteen patients had a totally endoscopic anastomosis, whereas in 61 a small mini-thoracotomy or mini-sternotomy was used. Sixteen patients (17.8%) were converted electively to a sternotomy: 11 patients underwent off-pump and 5 patients on-pump surgery. There were no deaths; 13 patients (14.4%) incurred one or more of the 11 major complication(s), including 5, 1, 2, 3, and 2 in each of the five quintiles (p = 0.39). Standard statistical analyses identified a significant decrease in operating room time (p < 0.0001), as well as a decrease in the incidence of an occluded graft or wrong vessel grafted from quintiles 1 to 5 (p = 0.03). On CUSUM analysis, the failure curve was steep for the first 18 to 20 patients, before moderating its slope for the remainder of the experience. CONCLUSIONS: Robotic ITA to coronary bypass on the beating heart has a moderately steep learning curve, which is mitigated by further experience. CUSUM analysis complimented standard statistical methods in detecting a cluster of suboptimal results during the early experience with this procedure.

Current status and future directions in computer-enhanced video- and robotic-assisted coronary bypass surgery.

Since 1997, both the Cleveland Clinic and London Health Sciences Centre groups have embraced robotic assistance and more recently demonstrated the efficacy of this technology in totally closed-chest, beating heart myocardial revascularization. This endeavor involved an orderly progression and the learning of new surgical skill sets. We review the evolution of robot-enhanced coronary surgery and forecast the future of endoscopic and computer-enhanced, robotic-enabling technology for coronary revascularization. This report describes a computer-assisted totally closed-chest coronary bypass operation, and preliminary results are discussed. The internal thoracic artery (ITA) was harvested through three 5-mm access ports and prepared and controlled endoscopically. A prototype sternal elevator was used to increase intrathoracic working space. A 10-mm endoscopic stabilizer was placed through the second intercostal space, and the left anterior descending coronary artery was controlled with silastic snares. Telerobotic anastomoses were completed end-to-side using custom-made, double-armed 8-0 polytetrafluroethylene sutures. To date, 84 patients have undergone successful myocardial revascularization with robotic assistance with a 0% surgical mortality rate. ITA harvest, anastomotic, and operating times for the entire group have been longer than for conventional surgery at 61.3 +/- 17.9 minutes, 28.5 +/- 28.2 minutes, and 368 +/- 129 minutes, respectively. Bleeding, ventilatory times, arrhythmias, hospital lengths of stay, and return to normal activity have been reduced. Recently, we have developed a new robotic revascularization strategy called Atraumatic Coronary Artery Bypass that is a promising mid-term step on the pathway to totally endoscopic, beating-heart coronary artery bypass. We conclude that computer-enhanced robotic techniques are safe, and further clinical studies are required to define the full potential of this evolving technology.

Robotic Surgery, the First 100 Cases: Where Do We Go from Here?

Abstract Background: Since the robot-assisted cardiac surgery program at this center was initiated in September 1998 the results have been regularly critically evaluated. We report a retrospective review of the first 100 robotic procedures and their evolution. Methods: Between September 1998 and May 2001, 146 patients underwent robot-assisted procedures. All procedures were performed using the Aesop robotically controlled camera or the Zeus robotic system. A harmonic scalpel was used for all internal thoracic artery (ITA) dissections whether the dissections were performed manually or with the Zeus robotic system. Results: There were 123 closed-heart and 23 open-heart procedures, which included 8 atrial-septal defect repairs, 11 mitral valve repairs, 4 mitral valve replacements, 57 Aesop ITA takedowns, 68 Zeus ITA takedowns, and 13 totally endoscopic coronary artery bypass grafts. Graft patency in Aesop and Zeus ITA takedown groups was 96%. All the patients were New York Heart Association class I after their procedures. Conclusion: With the development of surgical robots, it has been possible to perform endoscopic cardiac surgery for selected cases. Future directions will be demonstrated, including telementoring, telesurgery, and Zeus-assisted initiatives in cardiac surgery and other surgical disciplines.

Early experience with robotically assisted internal thoracic artery harvest.

We sought to determine the efficacy of using robotic assistance to facilitate endoscopic harvesting of internal thoracic arteries (ITAs). A total of 104 patients had ITAs harvested endoscopically with use of both the AESOP 3000 system (Computer Motion, Goleta, CA, U.S.A.) and Zeus robotic telesurgical system (Computer Motion). All ITAs were harvested with a harmonic scalpel (Ethicon Endosurgery, Cincinnati, OH, U.S.A.). With the left lung collapsed, ITAs were harvested with CO2 insufflation through three 5-mm ports in the left chest. All patients tolerated insufflation without hemodynamic compromise. Average ITA harvest time was 61.3 +/- 20.9 minutes. Intraoperative graft flows averaged 36.3 +/- 22.4 mL/min. There were three distal ITA injuries; all other vessels were patent after harvesting and demonstrated no angiographic evidence of injury. This article demonstrates a technique by which ITA can be safely harvested totally endoscopically with use of computer-enhanced robotic systems and a harmonic scalpel, allowing complete pedicle dissection through 5-mm ports with minimal ITA manipulation.

Early experience treating tricuspid valve endocarditis with a novel extracellular matrix cylinder reconstruction.

OBJECTIVE: The short-term outcomes were evaluated in patients treated for tricuspid valve endocarditis using a novel extracellular matrix (ECM) cylinder reconstruction technique. METHODS: Patients with clinically significant tricuspid regurgitation whose valves were not repairable by conventional techniques underwent valve replacement with a cylindrical construct sewn out of CorMatrix ECM (CorMatrix Cardiovascular, Roswell, Ga). The cylinders were sized to the native valve dimensions and attached distally to the papillary muscles using polypropylene sutures and ECM pledgets, and proximally to the annulus using a running suture. Patient data were collected retrospectively. RESULTS: From November 2011 to October 2013, 12 surgeons performed 19 tricuspid valve cylinder reconstructions in 8 men and 10 women (age range, 19-53 years). Of the 19 patients, 11 had active and 5 had treated endocarditis. One case was robotic-assisted. No deaths occurred, and no new cases of heart block developed. The papillary attachments were disrupted intraoperatively in 1 patient and after 7 days in another; both were successfully revised. A third patient experienced recurrent disruption of the implant at 13 and 22 months and ultimately received a pericardial valve. Fungal infection occurred in 1 cylinder at 6 months; a second ECM cylinder was implanted. Follow-up data were available for 13 patients at 1 to 2 months, 8 at 6 months, and 3 at 12 and 18 months. Other than patients undergoing reoperation, all showed well-functioning tricuspid valves with no to mild regurgitation. CONCLUSIONS: Cylinder reconstruction with ECM could be a suitable technique for replacing the tricuspid valve while preserving annuloventricular continuity in patients with infective endocarditis not repairable by conventional techniques.

A review of the current status of pericardial closure following cardiac surgery.

Some cardiac surgeons prefer to close the pericardium whenever possible following surgery, others specifically avoid this practice, and still others believe that neither alternative has any meaningful influence on clinical outcomes. Unfortunately, scientific evidence supporting either approach is scarce, making a consensus regarding best practice impossible. In this article, the known functions of the native intact pericardium are summarized, and the arguments for and against pericardial closure after surgery are examined. In addition, the techniques and materials that have been utilized for pericardial closure previously, as well as those that are currently being developed, are assessed.

Coronary artery bypass operations for elderly patients in California, 2003 to 2008.

BACKGROUND: Coronary artery bypass grafting (CABG) is no longer rare for elderly patients. This study evaluates operative mortality and the effects of off-pump CABG (OPCAB) on mortality for elderly Californians between 2003 and 2008. METHODS: All isolated CABGs in California for 2003 to 2008 were classified into cohorts by age: (1) younger than 75, (2) 75 to 84, and (3) 85 or older. Multivariable logistic regression models were developed for operative mortality. Trend analyses for observed and predicted mortality, and observed-to-expected mortality ratios were performed. The "recycled predictions" method was used to assess the effect of OPCAB on operative mortality. RESULTS: Among 101,710 isolated CABGs between 2003 and 2008, 22.0% were in cohort 2 and 2.3% were in cohort 3. Predicted mortality was unchanged for cohorts 2 and 3 (all p > 0.05), but observed-to-expected mortality ratios declined from 0.958 to 0.633 for cohort 2 (p = 0.021) and from 1.027 to 0.965 for cohort 3 (p = 0.168). The proportion of OPCAB for patients aged 75 years or older increased from 25.0% to 29.1% between 2003 and 2008. The adjusted odds ratio for operative mortality for OPCAB in patients aged 75 years or older was 0.752 (95% confidence interval, 0.650 to 0.871; p < 0.001) compared with on-pump CABG for the same age cohort. CONCLUSIONS: In California, overall predicted mortality was unchanged for elderly patients between 2003 and 2008, but operative mortality significantly decreased for patients aged 75 to 84. Improvement for CABG patients aged 85 years or older was insignificant. The increase in the number of OPCAB patients was associated with decreased mortality for elderly patients.

Long-term angiographic follow-up of robotic-assisted coronary artery revascularization.

BACKGROUND: Robotic-assisted coronary artery bypass grafting (CABG) has been shown in short-term studies to increase patient satisfaction and to reduce surgical morbidity and recovery times. However, the long-term patency rate of robotic-assisted CABG is unknown. Therefore, the objective of this study was to assess the long-term patency rate of robotic-assisted coronary artery bypass grafts. METHODS: The study cohort included all patients who underwent robotic-assisted conduit dissection for CABG at London Health Sciences Centre between September 1999 and December 2003. These patients had selective graft patency assessment using cardiac catheterization or computed tomography angiography (CTA), or both, and stress myocardial perfusion scintigraphy (MPS) 5 to 10 years after surgery to evaluate graft patency and to give functional information on the hemodynamic significance of any graft stenosis. Patients also completed quality of life questionnaires. RESULTS: From a total of 160 patients who underwent robotic-assisted CABG, 82 eligible patients were followed with graft patency assessments for a mean period of 8 years±16.3 months. The patency rate of all robotic-assisted CABG grafts in this patient cohort was 92.7%. The patency rate of left internal thoracic artery grafts to the left anterior descending artery after robotic-assisted CABG in this patient cohort was 93.4%. Patients consistently attained high scores on quality of life questionnaires after surgery. CONCLUSIONS: The long-term patency rate of grafts after robotic-assisted CABG was 92.7% at a mean follow-up period of 95.8±16.3 months. Specifically, the patency rate of left internal thoracic artery grafts to the left anterior descending artery after robotic-assisted CABG was 93.4%.