Technique of Complete Heart Isolation with Continuous Cardiac Perfusion During Cardiopulmonary Bypass: New Opportunities for Gene Therapy.

Cardiopulmonary bypass (CPB) featuring complete heart isolation and continuous cardiac perfusion is a very promising approach for solving the problem of efficient gene delivery. In the technique presented here, separate pumps are used for the systemic and cardiac circuits. This system permits continuous isolated arrested heart perfusion through optimizing a number of delivery parameters including temperature, flow rate, driving pressure, ionic composition, and exposure time to the cardiac vessels. During complete cardiac isolation, the blood vector concentration trended from 11.51 ± 1.73 log genome copies (GCs)/cm3 to 9.84 ± 1.65 log GC/cm3 (p > .05). Despite restructuring a very high concentration to the heart, GCs were detectable in the systemic circuit. These values over time were near negligible by comparison but detectable 1.66 ± .26 during 20 minutes of recirculation and did not change (p > .05). After the completion of the recirculation interval and subsequent washing procedure, the initial systemic blood vector GC concentration slightly increased to 2.08 ± .38 log GCs/cm3 (p > .05). During the recirculation period, we supported flow via the cardiac circuit around 300 mL/min. In this technique of heart isolation with continuous cardiac perfusion, >99% of the vector remains in coronary circulation during recirculation period. The animal's non recirculation blood, or that in the system, was routinely tested during and after recirculation to contain much less than 1% of the original dose obtained via logging concentration of therapeutic over time. All of the sheep in this group recovered from anesthesia and received critical postoperative care, including all organ function, in the first 24-36 hours. Twenty-one sheep (84%) survived to euthanasia at 12 weeks. Average CPB time was 107 ± 19.0 minutes and cross-clamp time was 49 ± 7.9 minutes. This technology readily provides multiple pass recirculation of genes through the heart with minimal side effects of collateral expression of other organs.

Safety and efficacy of high-dose adeno-associated virus 9 encoding sarcoplasmic reticulum Ca(2+) adenosine triphosphatase delivered by molecular cardiac surgery with recirculating delivery in ovine ischemic cardiomyopathy.

OBJECTIVE: Therapeutic safety and efficacy are the basic prerequisites for clinical gene therapy. We investigated the effect of high-dose molecular cardiac surgery with recirculating delivery (MCARD)-mediated adeno-associated virus 9 (AAV9)/sarcoplasmic reticulum Ca(2+) adenosine triphosphatase (SERCA2a) gene delivery on clinical parameters, oxidative stress, humoral and cellular immune responses, and cardiac remodeling. METHODS: Ischemic cardiomyopathy was generated in a sheep model. The sheep were assigned to 1 of 2 groups: control (n = 10) and study (MCARD, n = 6). The control group underwent no intervention and the study group received 10(14) genome copies of AAV9/SERCA2a 4 weeks after infarction. RESULTS: Our ischemic model produced reliable infarcts leading to heart failure. The baseline ejection fraction in the MCARD group was 57.6% ± 1.6% versus 61.2% ± 1.9% in the control group (P > .05). At 12 weeks after infarction, the MCARD group had superior left ventricular function compared with the control group: stroke volume index, 46.6 ± 1.8 versus 35.8 ± 2.5 mL/m(2) (P < .05); ejection fraction, 46.2% ± 1.9% versus 38.7% ± 2.5% (P < .05); and left ventricular end-systolic and end-diastolic dimensions, 41.3 ± 1.7 versus 48.2 ± 1.4 mm and 51.2 ± 1.5 versus 57.6 ± 1.7 mm, respectively (P < .05). The markers of oxidative stress were significantly reduced in the infarct zone in the MCARD group. No positive T-cell-mediated immune response was seen in the MCARD group at any point. Myocyte hypertrophy was also significantly attenuated in the MCARD group compared with the control group. CONCLUSIONS: Cardiac overexpression of the SERCA2a gene by way of MCARD is a safe therapeutic intervention. It significantly improves left ventricular function, decreases markers of oxidative stress, abrogates myocyte hypertrophy, arrests remodeling, and does not induce a T-cell-mediated immune response.

Cardiac surgical delivery of the sarcoplasmic reticulum calcium ATPase rescues myocytes in ischemic heart failure.

BACKGROUND: The sarcoplasmic reticulum calcium ATPase (SERCA2a) is an important molecular regulator of contractile dysfunction in heart failure. Gene transfer of SERCA2a mediated by molecular cardiac surgery with recirculating delivery (MCARD) is a novel and clinically translatable strategy. METHODS: Ischemic heart failure was induced by ligation of OM1 and OM2 in 14 sheep. Seven sheep underwent MCARD-mediated AAV1-SERCA2a delivery 4 weeks after myocardial infarction, and seven sheep served as untreated controls. Magnetic resonance imaging-based mechanoenergetic studies were performed at baseline, 3 weeks, and 12 weeks after infarction. Myocyte apoptosis was quantified by Tdt-mediated nick-end labeling assay. Myocyte cross-sectional area and caspase-8 and caspase-9 activity was measured with imaging software, specific fluorogenic peptides, and immunohistochemistry. RESULTS: MCARD-mediated AAV1-SERCA2a gene delivery resulted in robust cardiac-specific SERCA2a expression and stable improvements in global and regional contractility. There were significantly higher stroke volume index, left ventricular fractional thickening, and ejection fraction at 12 weeks in the MCARD group than in the control group (30 ± 3 vs 21 ± 2 mL/m(2); 12% ± 5% vs 3% ± 3%; and 43 ± 4 vs 32 ± 4, respectively, all p < 0.05). Apoptotic myocytes were observed more frequently in the control group than in the MCARD-SERCA2a group (0.57.2 ± 0.16 AU vs 0.32.4 ± 0.08 AU, p < 0.05). MCARD-SERCA2a also resulted in decreased caspase-8 and caspase-9 expression and decreased myocyte area in the border zone of transgenic sheep compared with control sheep (14.6% ± 1.2% vs 2.9% ± 0.7%; 18.2% ± 1.9% vs 8.6% ± 1.4%; and 102.1 ± 3.8 µm(2) vs 88.1 ± 3.6 µm(2), all p < 0.05). CONCLUSIONS: MCARD-mediated SERCA2a delivery results in robust cardiac specific gene expression, improved contractility, and a decrease in both myocyte apoptosis and myocyte hypertrophy.

Cardiac surgery in Jehovah's Witness patients: ten-year experience.

BACKGROUND: Cardiac surgery in Jehovah's Witnesses poses unique challenges. We have developed a comprehensive multimodality program for these patients and have obtained excellent results. METHODS: Ninety-one Jehovah's Witness patients underwent cardiac surgery between 2000 and 2010. Preoperative, intraoperative, and postoperative considerations in the conduct of bloodless surgery in the Jehovah's Witness population are discussed. Mortality for isolated coronary artery bypass graft surgery and isolated aortic valve replacement was compared with predicted mortality from The Society of Thoracic Surgeons (STS) risk models. Perioperative outcomes were stratified by urgent and elective status of operations. RESULTS: Mean age was 65±12.4 years. Comorbid conditions included hypertension (84.6%), diabetes mellitus (48.4%), previous myocardial infarction (23.1%), chronic lung disease (38.5%), peripheral vascular disease (20.9%), and renal failure (11%). In-hospital mortality was 5.5% (n=5). Mortality for isolated coronary artery bypass graft surgery and isolated aortic valve replacement was 2.2% (observed to expected ratio=1.05, 95% confidence interval: 0 to 3.02) and 5.6% (observed to expected=1.46, 95% confidence interval: 0 to 3.76), respectively. Other complications included reoperation (all=8.8%, cardiac=2.2%), sepsis (2.2%), sternal wound infection (1.1%), transient ischemic attack (1.1%), renal failure requiring dialysis (1.1%), and prolonged ventilation (18.7%). Major complication rates were not significantly different between the elective group and the urgent group. CONCLUSIONS: Bloodless cardiac surgery in Jehovah's Witness patients can be performed with excellent outcomes in both elective and urgent situations. Mortality rates for isolated coronary artery bypass graft surgery and isolated aortic valve replacement are within the expected 95% confidence intervals of STS predicted mortality.

Reoperative cardiac surgery in Jehovah's witness patients with patent internal thoracic artery grafts: how far can we push the envelope?

Reoperative cardiac surgery in Jehovah's Witness (JW) patients with patent internal mammary arteries is a formidable surgical challenge. We have successfully performed 2 such cases using creative approaches. The first patient, a morbidly obese woman, presented with an acute coronary syndrome 4 years after off-pump coronary artery bypass grafting (CABG) with a hemoglobin of 10 gm/dL. She was stabilized with stenting of the culprit vessel; erythropoietin therapy was performed to increase her hemoglobin, and surgery was performed electively. The internal thoracic artery (ITA) was dissected and clamped, and intermittent cardioplegia was used for myocardial protection. The second patient needed aortic valve replacement 3 years after a previous CABG using an ITA. Limited dissection was used at redo operation without exposing the ITA. Aortic valve replacement was performed under cold fibrillatory arrest with an open ITA. Successful reoperative cardiac surgery in JW patients requires preoperative preparation using a multidisciplinary team approach and flexible operative planning.

Minimally invasive cardiac surgery using a flexible aortic clamp.

Minimally invasive surgery for mitral valve disease has been performed using a variety of technologies, some of which are complex, have a steep learning curve, and are expensive. We have adopted a simple cost-effective approach over the last 7 years to perform a variety of minimally invasive procedures with excellent outcomes. There have been no strokes, no mortalities, and no episodes of limb ischemia in our series. No patient has required reoperation.

Bicuspidization of the tricuspid valve for the treatment of posterior leaflet endocarditis: a case report.

Patients who require surgical therapy for the treatment of tricuspid valve regurgitation can avoid undergoing tricuspid valve replacement if valve-sparing repair techniques are employed. Tricuspid valvular endocarditis frequently requires valvectomy, leaving the right side of the heart and pulmonary system vulnerable to unregulated blood flow. We present a case of complete posterior leaflet excision and plication of the involved portion of the tricuspid annulus, which resulted in "bicuspidization" of the valve, for the treatment of tricuspid valve endocarditis localized to the posterior leaflet.

Resection of a large atrial hemangioma using a bloodless surgical technique: a case report.

We present a biatrial hemangioma in a Jehovah's Witness patient. Hemangioma is extremely rare, accounting for 1% to 2% of benign cardiac tumors. Complete resection of a large hemangioma is mandatory due to its potentially life-threatening risk. In Jehovah's Witness patients, it is necessary to employ bloodless surgery protocols to maximize the patient's outcome. Our patient had undergone 6 weeks of monitoring and erythropoietin therapy prior to surgery, raising her hemoglobin level from 11.6 g/dL to 16.8 g/dL. Intraoperative bloodless surgical protocols as well as a continuous blood circuit were utilized. The patient's hemoglobin level on postoperative day one was 14.5 g/dL; one year postsurgery, the patient was symptom free.