Prem S. Shekar

Early and late outcomes of 1000 minimally invasive aortic valve operations.

OBJECTIVE Minimal access cardiac valve surgery is increasingly utilized. We report our 11-year experience with minimally invasive aortic valve surgery. METHODS From 07/96 to 12/06, 1005 patients underwent minimally invasive aortic valve surgery. Early and late outcomes were analyzed. RESULTS Median patient age was 68 years (range: 24-95), 179 patients (18%) were 80 years or older, 130 patients (13%) had reoperative aortic valve surgery, 86 (8.4%) had aortic root replacement, 62 (6.1%) had concomitant ascending aortic replacement, and 26 (2.6%) had percutaneous coronary intervention on the day of surgery (hybrid procedure). Operative mortality was 1.9% (19/1005). The incidences of deep sternal wound infection, pneumonia and reoperation for bleeding were 0.5% (5/1005), 1.3% (13/1005) and 2.4% (25/1005), respectively. Median length of stay was 6 days and 733 patients (72%) were discharged home. Actuarial survival was 91% at 5 years and 88% at 10 years. In the subgroup of the elderly (> or =80 years), operative mortality was 1.7% (3/179), median length of stay was 8 days and 66 patients (37%) were discharged home. Actuarial survival at 5 years was 84%. There was a significant decreasing trend in cardiopulmonary bypass time, the incidence of bleeding, and operative mortality over time. CONCLUSIONS Minimal access approaches in aortic valve surgery are safe and feasible with excellent outcomes. Aortic root replacement, ascending aortic replacement, and reoperative surgery can be performed with these approaches. These procedures are particularly well-tolerated in the elderly.

Defective DNA Replication Impairs Mitochondrial Biogenesis In Human Failing Hearts

Rationale: Mitochondrial dysfunction plays a pivotal role in the development of heart failure. Animal studies suggest that impaired mitochondrial biogenesis attributable to downregulation of the peroxisome proliferator-activated receptor &ggr; coactivator (PGC)-1 transcriptional pathway is integral of mitochondrial dysfunction in heart failure. Objective: The study sought to define mechanisms underlying the impaired mitochondrial biogenesis and function in human heart failure. Methods and Results: We collected left ventricular tissue from end-stage heart failure patients and from nonfailing hearts (n=23, and 19, respectively). The mitochondrial DNA (mtDNA) content was decreased by >40% in the failing hearts, after normalization for a moderate decrease in citrate synthase activity (P<0.05). This was accompanied by reductions in mtDNA-encoded proteins (by 25% to 80%) at both mRNA and protein level (P<0.05). The mRNA levels of PGC-1&agr;/&bgr; and PRC (PGC-1–related coactivator) were unchanged, whereas PGC-1&agr; protein increased by 58% in the failing hearts. Among the PGC-1 coactivating targets, the expression of estrogen-related receptor &agr; and its downstream genes decreased by up to 50% (P<0.05), whereas peroxisome proliferator-activated receptor &agr; and its downstream gene expression were unchanged in the failing hearts. The formation of D-loop in the mtDNA was normal but D-loop extension, which dictates the replication process of mtDNA, was decreased by 75% in the failing hearts. Furthermore, DNA oxidative damage was increased by 50% in the failing hearts. Conclusions: Mitochondrial biogenesis is severely impaired as evidenced by reduced mtDNA replication and depletion of mtDNA in the human failing heart. These defects are independent of the downregulation of the PGC-1 expression suggesting novel mechanisms for mitochondrial dysfunction in heart failure.

The Influence of Epiaortic Ultrasonography on Intraoperative Surgical Management in 6051 Cardiac Surgical Patients

BACKGROUND Intraoperative echocardiography has become a mainstay monitor of cardiac function and a popular diagnostic tool in patients undergoing cardiac procedures. Previous reports suggest that epiaortic ultrasonography (EU) is superior to transesophageal echocardiography and manual palpation in identifying ascending aortic atheroma. Its impact on surgical decision making has not been thoroughly investigated, however. METHODS We retrospectively analyzed the medical records of 6051 consecutive patients who underwent EU of their ascending aorta during cardiac operations between 1996 and 2006 to determine a potential impact on intraoperative surgical decision making. Aortic atheroma was graded according to standard classification. Neurologic complications were evaluated according to the Society of Thoracic Surgeon definition for stroke and transient ischemic attack (TIA). RESULTS The overall impact of EU on surgical decision making was 4.1% and included a change in the technique for inducing cardiac arrest in 1.8%, aortic atherectomy or replacement surgery in 0.8%, requirement for off-pump coronary artery bypass grafting (CABG) in 0.6%, avoidance of aortic cross-clamping and use of ventricular fibrillatory arrest in 0.5%, change in arterial cannulation site in 0.2%, or avoidance of aortic cannulation in 0.2%. The greatest affect of EU was observed in patients undergoing combined CABG with aortic/mitral valve procedures (6.7%). The smallest impact was seen in patients undergoing mitral valve operations (1.4%). Aortic atheroma was more frequent on the anterior aspect of the aorta (n = 171) in patients with a change in surgical plan than on the posterior aspect (n = 78). The overall stroke rate was lower in patients with intraoperative EU compared with all patients undergoing surgical procedures. CONCLUSIONS Epiaortic ultrasonography is a useful technique to detect ascending aortic atheroma, has a significant impact on surgical decision making in more than 4% of cardiac surgical patients, and might result in improved perioperative neurologic outcome.

Minimally invasive aortic valve replacement in octogenarian, high-risk, transcatheter aortic valve implantation candidates

OBJECTIVE Risk-stratifying algorithms are currently used to determine which patients may be at prohibitive risk for surgical aortic valve replacement, and thus candidates for transcatheter aortic valve implantation. Minimally invasive surgical approaches have been successful in reducing morbidity and improving survival after aortic valve replacement, especially in octogenarians. We documented outcomes after minimally invasive aortic valve replacement in high-risk octogenarians who may be considered candidates for percutaneous/transapical aortic valve replacement. METHODS From 1996 to 2009, minimally invasive aortic valve replacement was performed in 249 consecutive octogenarians. We used the modified European System for Cardiac Operative Risk Evaluation and Society of Thoracic Surgeons score to risk-stratify patients and characterize all early and late results. RESULTS The mean age at operation was 84±3 (range 80-95) years, and 111 patients (45%) were male. Twenty-one percent (n=52) had previous cardiac surgery. Operative mortality was 3% (n=8/249). The median modified European System for Cardiac Operative Risk Evaluation (11%; interquartile range, 6-14) and Society of Thoracic Surgeons score (10.5%; interquartile range, 7-17) were not predictive of 30-day mortality in this cohort of patients (European System for Cardiac Operative Risk Evaluation c-index=0.527, P=.74, Society of Thoracic Surgeons score c-index=0.67, P=.18). Despite their poor predictive power, the Society of Thoracic Surgeons score and European System for Cardiac Operative Risk Evaluation were correlated with each other (r=0.40, P<.0001). Postoperative complications included stroke in 10 patients (4%), pneumonia in 3 patients (1%), renal failure requiring dialysis in 2 patients (1%), cardiac arrest in 2 patients (1%), pulmonary embolism in 1 patient (1%), and sepsis in 1 patient (1%). Follow-up was available for 238 patients (96%) and extended up to 12 years. Overall, long-term survival after minimally invasive aortic valve replacement at 1, 5, and 10 years was 93%, 77%, and 56%, respectively. There was no significant difference in long-term survival compared with that of a US age- and gender-matched population (standardized mortality ratio, 1.01; 95% confidence interval, 0.76-1.37; P=.88). A multivariate Cox-proportional hazards model indicated that increasing age (hazard ratio, 1.10; P=.008) and severe chronic obstructive pulmonary disease (hazard ratio, 2.52; P<.007) were significant predictors of survival. By using these factors, a clinical prediction model (P=.02) was developed and demonstrated that low-risk patients (first quartile prediction score) had 1-, 5-, and 8-year survival of 94%, 84%, and 67%, whereas high-risk patients (third quartile prediction score) had 1-, 5-, and 8-year survival of 89%, 74%, and 49%, respectively. CONCLUSIONS Patients thought to be high-risk candidates for surgical aortic valve replacement have excellent outcomes after minimally invasive surgery with long-term survival that is no different than that of an age- and gender-matched US population. These data provide a benchmark against which outcomes of transcatheter aortic valve implantation could be compared.

Reoperative minimal access aortic valve surgery: Minimal mediastinal dissection and minimal injury risk

OBJECTIVE Minimizing surgical access in reoperative cardiac surgery allows limitation of dissection, trauma, and manipulation of patent bypass grafts. We report an 11-year experience with reoperative minimal access aortic valve surgery through an upper hemisternotomy. METHODS From July 1996 to June 2007 at our institution, 146 patients underwent reoperative minimal access aortic valve surgery, 109 of whom had undergone previous coronary artery bypass grafting and 93 of whom had a patent left internal thoracic artery graft. In patients with a patent left internal thoracic artery graft, the graft remained undissected. Myocardial protection was achieved with hypothermia, cold cardioplegia, and systemic hyperkalemia. Early and late outcomes were analyzed. RESULTS Median age was 76 years, and 43 patients (29%) were 80 years or older. Nineteen patients(13%) underwent concomitant procedures, such as coronary artery bypass grafting, mitral valve repair, and ascending aortic replacement. Median cardiopulmonary bypass and aortic crossclamp times were 150 and 80 minutes, respectively. Four patients (2.8%) had conversion to full sternotomy. Operative mortality was 4.1% (6/146). The incidences of reoperation for bleeding and blood transfusion were 0.7% (1/146) and 83.6% (122/146), respectively. No patient had left internal thoracic artery or aortocoronary graft injury. Median stay was 8 days, and 56% (79/140) were discharged home. Five-year actuarial survival was 85%. CONCLUSION An upper hemisternotomy approach for reoperative aortic valve surgery is safe and feasible. This approach minimizes tissue dissection and trauma, thereby reducing the risk of injury to patent grafts and mediastinal organs.

Surgical treatment of bicuspid aortic valve disease: Knowledge gaps and research perspectives

Supplemental material is available online.Sempre la praticadeveessereedificata sopra la bonateorica. [Practice must always be founded on soundtheory.]—Leonardo Da Vinci (1452-1519; providedthe firstdepiction of abicuspid aorticvalve).Research on bicuspid aortic valves (BAV) and associatedconditions is increasing exponentially. A major part of thecurrent knowledge on BAV is derived from investigationscarried out in the clinical setting, especially the surgicalsetting, as a consequence of the epidemiologic and surgicalimportance of its valvular and vascular complications. Forexample, most of the stenotic valves explanted at the timeof aortic valve replacement are congenitally malformed.

On-Pump and Off-Pump Coronary Artery Bypass Grafting

Surgery for coronary artery disease is known as coronary artery bypass grafting (CABG). It was one of the landmark operations in the history of cardiac surgery that rescued millions of people afflicted by coronary artery disease. It was first performed by Kolesov,1 was popularized by Favaloro,2 and is still the leading heart operation performed today. Current reasons for performing CABG are the presence of 3-vessel disease (all the 3 major arteries to the heart are blocked), left main coronary artery disease (the main artery itself is critically narrowed), and 3-vessel disease in diabetics. It also is used for patients with severely depressed heart function and for patients who need surgery for heart conditions in addition to coronary artery disease (such as replacement of valves or reconstruction of the heart muscle). Similar to a detour on a highway in the setting of a roadblock, CABG involves the strategic placement of bypass grafts that will provide an alternative route for the blood to flow around the blockage (Figure). These bypass grafts are composed of other arteries and veins from the body of the patient that are harvested only when they are numerous in their location or their function in their primary location can be safely and effectively taken over by …

Surgical Embolectomy for Acute Massive and Submassive Pulmonary Embolism in a Series of 115 Patients

BACKGROUND Pulmonary embolectomy is often indicated for central pulmonary embolism (PE) with hemodynamic instability, but remains controversial for hemodynamically stable patients with signs of right ventricular dysfunction. Because thrombolytic therapy is often contraindicated postoperatively, we reviewed risk factors and outcomes of pulmonary embolectomy for stable and unstable central PE, particularly in the early postoperative period. METHODS Between October 1999 and September 2013, 115 patients underwent pulmonary embolectomy for central, hemodynamically unstable PE (49 of 115, 43%) or hemodynamically stable PE (56 of 115, 49%). Ten operations for alternate indications (right atrial mass, endocarditis) were excluded for comparison analysis, leaving 105 patients. RESULTS Mean age was 59 ± 13 years; 46 of 105 patients (44%) had recent surgery (within 5 weeks): orthopedic (12 of 46, 25%), neurosurgery (11 of 46, 24%), or general surgery (10 of 46, 22%). Preoperative demographics did not differ between groups, except for the frequency of cardiopulmonary resuscitation among unstable patients (11 of 49, 22%) versus stable patients (0 of 56, 0%; p < 0.001). Operative mortality for the combined groups was 6.6% (7 of 105): unstable 10.2% (5 of 49) versus stable 3.6% (2 of 56; p = 0.247). Of 11 patients requiring preoperative cardiopulmonary resuscitation, 4 died. Six-month, 1-year, and 3-year survival rates were, respectively, 75%, 68.4%, and 65.8% for unstable PE, and 92.6%, 86.7%, and 80.4% for stable PE (p = 0.018). CONCLUSIONS This large series of pulmonary embolectomies demonstrates excellent early and late survival rates for patients with stable PE and unstable PE. These findings confirm pulmonary embolectomy as a beneficial therapeutic option for central PE, especially during the postoperative period when thrombolytic therapy is often contraindicated.

Ventricular Assist Devices for Durable Support

What can we offer a 70-year-old retired schoolteacher hospitalized with congestion for the third time in 6 months? The LVEF is 21%. Shortness of breath interrupts sleeping and dressing, and peak oxygen consumption of 9 mL/kg per minute confirms NYHA Class IV status. He has noninsulin-dependent diabetes and chronic coronary artery disease, with patent grafts to thin-caliber vessels. His systolic blood pressure is 88 mm Hg and jugular venous pressure of 15 cm. Angiotensin-converting enzyme inhibitor (ACEI) and spironolactone were stopped during his last hospitalization because of progressive increase in serum creatinine to 3.8 mg/dL, currently 2.7, estimated clearance of 25 cc/min, and proteinuria. His regimen includes low doses of hydralazine and isosorbide dinitrate and digoxin, and he cannot tolerate beta-blockers. Although he is followed in an advanced heart failure management program, fluid retention has recurred despite torsemide 200 mg twice daily, intermittent metolazone, and compliance with 2-L fluid restriction, 2-g sodium diet, and daily weights. Serum sodium is 135 mEq/L, and B-type natriuretic protein (BNP) level is 1822 pg/mL. He expresses a willingness to try anything to feel better. This patient has recurrent heart failure despite having received the standard therapies known to improve outcome and clinical status.1 Renal dysfunction would preclude cardiac transplantation, which, in the setting of limited donor availability, would not often be offered to patients in this age group with major comorbidities. In patients with comprehensive home support, chronic inotropic infusion might be considered for palliation of end-stage symptoms, understanding that death is imminent and may be accelerated by inotropic therapy. For most patients with refractory “stage D” heart failure,2 the focus should shift toward comfort and planning with patient and family (Figure 1). Figure 1. Stream diagram demonstrating evaluation sequence for small number of patients not eligible for transplant but eligible for …

Heparin Concentration–Based Anticoagulation for Cardiac Surgery Fails to Reliably Predict Heparin Bolus Dose Requirements

BACKGROUND:Hemostasis management has evolved to include sophisticated point-of-care systems that provide individualized dosing through heparin concentration–based anticoagulation. The Hepcon HMS Plus system (Medtronic, Minneapolis, MN) estimates heparin dose, activated clotting time (ACT), and heparin dose response (HDR). However, the accuracy of this test has not been systematically evaluated in large cohorts. METHODS:We examined institutional databases for all patients who underwent cardiac surgery with cardiopulmonary bypass (CPB) at our institution from February 2005 to July 2008. During this period, the Hepcon HMS Plus was used exclusively for assessment of heparin dosing and coagulation monitoring. Detailed demographic, surgical, laboratory, and heparin dosing data were recorded. ACT, calculated and measured HDR, and heparin concentrations were recorded. Performance of the Hepcon HMS Plus was assessed by comparison of actual and target ACT values and calculated and measured HDR. RESULTS:In 3880 patients undergoing cardiac surgery, heparin bolus dosing to a target ACT resulted in wide variation in the postheparin ACT (r2 = 0.03). The postheparin ACT did not reach the target ACT threshold in 7.4%(i.e., when target ACT was 300 s) and 16.9% (i.e., when target ACT was 350 s) of patients. Similarly, the target heparin level calculated from the HDR did not correlate with the postbolus heparin level, with 18.5% of samples differing by more than 2 levels of the assay. Calculated and measured HDR were not linearly related at any heparin level. CONCLUSIONS:The Hepcon HMS Plus system poorly estimates heparin bolus requirements in the pre-CPB period. Further prospective studies are needed to elucidate what constitutes adequate anticoagulation for CPB and how clinicians can reliably and practically assess anticoagulation in the operating room.