Comprehensive and Integrative Experimentation Setup for Large Animal Hybrid Valvular Heart Surgery.

BACKGROUND: Experimental surgical procedures for atrioventricular valves present promising translational capabilities, and preclinical studies are necessary to assess their applicability and to train young enthusiastic heart teams. Here, we present a synopsis of experimental surgical procedures on porcine models for mitral valvular (MV) and tricuspid valvular (TV) interventions; mitral valve-in-valve implantation (MViV), transapical cardioscopic (TAC) MV replacement (MVR), TAC-MV annuloplasty, and tricuspid valve-in-a-ring (TViR) procedures. METHODS: Twenty-five (n = 25) female Yorkshire pigs of 55-65 kg is the total number used in the four approaches; seven animals underwent MViV, six TAC-MVR, six TAC-MV annuloplasty, and six TViR, respectively. All were subjected to a first conventional valvular surgery (bioprosthetic valve replacement and/or prosthetic ring repair). Then, after 4 wk, a less-invasive second surgery was performed using the transcatheter approaches under investigation. Except for the TAC-MVR and annuloplasty procedures, all animals were followed up for additional 4 wk. RESULTS: (1) MViV (n = 7): Standard MVR was successfully performed in all animals. Transvalvular pressure gradients and flow velocities were (Pmax 3.77 ± 0.8 mmHg; Pmean 2.1 ± 0.6 mmHg, Vmax 97 ± 13 cm/s; Vmean 68 ± 21 cm/s). Effective MViV followed (Pmax 16.7 ± 1.8 mmHg; Pmean 6.2 ± 1.2 mmHg, Vmax 216 ± 32 cm/s; Vmean 110 ± 24 cm/s). (2) TAC-MVR (n = 6): The overall bypass time was 177.2 ± 44.2 min. Transprosthetic Pmean was 4.6 ± 2.4 mmHg; no paravalvular leaks in all animals. (3) TAC-MV annuloplasty (n = 6): The implantation time was 47 ± 6 min. MV was competent, left ventricular ejection fraction (LV-EF%) was 63 ± 4%. (4) TViR (n = 6): Conventional TV ring repair was performed in all animals (Pmax 2.42 ± 0.7 mmHg; Pmean 1.3 ± 0.6 mmHg, Vmax 82 ± 10.4 cm/s; Vmean 65.4 ± 21 cm/s). All TViRs were implanted efficiently (Pmax 4.7 ± 1.6 mmHg; Pmean 2.7 ± 0.8 mmHg, Vmax 105 ± 31 cm/s; Vmean 81 ± 16 cm/s). A mild paravalvular leak was observed in one animal (16%). CONCLUSIONS: All studied experimental valvular interventions are feasible, within the context of well-trained cardiac surgery specialists, and all possibilities should be considered when treating a patient to determine which one suits best his individual challenges and scope.

On-pump transapical cardioscopic mitral valve replacement with cardiac arrest: short-term results in a porcine survival model.

OBJECTIVES: Favourable outcomes with mitral annuloplasty have been achieved with transapical cardioscopic (TAC) surgery in a survival animal model. In addition, experimental TAC on a non-survival animal model also showed adequate access to remove the native mitral valve and implant a prosthetic valve, but the surgical procedure took a long time and lacked follow-up data. The goal of this study was to develop a clinically translatable TAC mitral valve replacement (MVR) procedure using technical and instrumental refinements to reduce the surgical time and to evaluate functional recovery and short-term durability using a survival porcine model. We hypothesized that MVR could be achieved with subannular implantation of the bioprosthesis via the TAC approach. METHODS: TAC MVR using the Hancock II™ (Medtronic)® mitral prosthesis was performed in 6 pigs via an incision over the xiphoid process, under cardiopulmonary bypass and cardiac arrest. COR-KNOT® and minimally invasive cardiac surgery instruments were used. Haemodynamics, echocardiography, cardiac computed tomography, ventriculography and electrocardiography were used to evaluate the function of the mitral prosthesis and left ventricle, coronary system and conduction system in the perioperative period and 4 weeks later. RESULTS: A postimplant examination showed that the mitral prosthesis was competent, without a paravalvular leak. The left ventricular ejection fraction was comparable to preoperative values (65.2 ± 4.1 vs 67.2 ± 7.9). The bypass, cross-clamp and implant times were 177.2 ± 44.2 min, 135.3 ± 47.6 min and 94.0 ± 41.2 min, respectively. The prosthesis was in a good position. The apical scar was intact and not aneurysmal 4 weeks after the implant. The valve was properly sutured to the annulus, without a postimplant paravalvular leak. All animals recovered after 1 month of follow-up with preserved ventricular function and normal wall motion. CONCLUSIONS: We successfully managed to replace the mitral valve with a biological prosthesis via the apex with encouraging bypass and cross-clamp times. This technique may provide an alternative for a selected group of patients with diseased mitral valves who have indications for MVR and still in a high-risk redo setting with conventional sternotomy or minimally invasive cardiac surgery-MVR.

Transapical cardioscopic mitral annuloplasty: a short-term survival study in a porcine model.

OBJECTIVES: The transapical approach provides concurrent surgical access to the mitral and the aortic valves, the root of the aorta and the left atrium. We previously showed the feasibility of transapical cardioscopic (TAC) surgery in a non-survival porcine model. However, reproducibility and feasibility of ring implantation using TAC have not been reported. Therefore, in this study, we hypothesized that implantation of a mitral annuloplasty ring can be feasibly and safely carried out endoscopically via the apex of the heart. METHODS: Using a porcine model in a short-term survival study, TAC mitral annuloplasty was performed in 6 pigs via an incision over the xyphoid, under cardiopulmonary bypass and cardiac arrest. A mitral annuloplasty ring was implanted via the apex to a normal mitral annulus, using a customized set of instruments and techniques. Haemodynamics, echocardiography, cardiac computed tomography, ventriculography, electrocardiography and histopathology studies were used to evaluate the function of the mitral valve and the left ventricle, coronary system and conduction system in the perioperative period and 4 weeks later. RESULTS: All 6 animals survived and recovered from the TAC annuloplasty procedure. Postimplantation examination showed that the mitral valve was competent, left ventricular ejection fraction was 63 ± 4%, left ventricular length was 6.2 ± 0.5 cm and left ventricular end-diastolic volume was 80 ± 10 ml, which were comparable to preoperative values. Apart from a dense scar at the apex, no significant injury was noticed on the ventricle, the chordae and the mitral leaflets. The bypass, cross-clamp and implantation times were 181 ± 55 min, 130 ± 37 min and 47 ± 6 min, respectively. CONCLUSIONS: Despite long surgical times due to the initial learning curve, successful execution of mitral ring annuloplasty could be safely achieved using the TAC approach, via a small incision without the involvement of sternum or the right pleural cavity, thereby potentially expanding the indication to patients with high-risk full sternotomy or right thoracotomy.

Pericardial effusion following cardiac surgery. A single-center experience.

Background Pericardial effusion is still a common postoperative complication after open heart surgery with cardiopulmonary bypass. Pericardial effusion significantly prolongs the hospital stay and associated costs as well as affecting overall outcomes after open heart surgery in Hanoi Heart Hospital, a tertiary hospital in Vietnam with an annual volume of 1000 patients. This study aimed to investigate the clinical presentation, incidence, and risk factors of postoperative pericardial effusion, which may ensure better prevention of pericardial effusion and improvement in surgical outcomes after open heart surgery. Methods A cross-sectional study was performed on 1127 patients undergoing open heart surgery from January 2015 to December 2015. Results Thirty-six (3.19%) patients developed pericardial effusion. Of these, 16 (44.4%) had cardiac tamponade. Pericardial effusion occurred after valve procedures in 77.8% of cases. Pericardial effusion was detected after discharge in 47.2% of cases at a mean time of 18.1 ± 13.7 days. Univariate logistic regression analysis showed that age > 25 years, body surface area ≥ 1.28 m2, preoperative liver dysfunction, New York Heart Association class III/IV, left ventricular end-diastolic diameter z score ≥ 0.55, and postoperative anticoagulant use were associated with postoperative pericardial effusion. Multivariate logistic regression analysis showed that left ventricular end-diastolic diameter z score ≥ 0.55 was an independent risk factor for postoperative pericardial effusion. Conclusions Routine postoperative echocardiography is necessary to detect postoperative pericardial effusion. Increased left ventricular end-diastolic dimension is an independent predictor of postoperative pericardial effusion.

An autologous platelet-rich plasma hydrogel compound restores left ventricular structure, function and ameliorates adverse remodeling in a minimally invasive large animal myocardial restoration model: a translational approach: Vu and Pal "Myocardial Repair: PRP, Hydrogel and Supplements".

AIMS: Cell-based myocardial restoration has not penetrated broad clinical practice yet due to poor cell retention and survival rates. In this study, we attempt a translational, large-scale restorative but minimally invasive approach in the pig, aiming at both structurally stabilizing the left ventricular (LV) wall and enhancing function following ischemic injury. METHODS AND RESULTS: A myocardial infarction (MI) was created by permanent ligation of left circumflex coronary artery through a small lateral thoracotomy. Thirty-six Yorkshire pigs were randomized to receive transthoracic intramyocardial injection into both infarct and border zone areas with different compounds: 1) Hyaluronic acid-based hydrogel; 2) autologous platelet-rich plasma (PRP); 3) ascorbic acid-enriched hydrogel (50 mg/L), combined with IV ibuprofen (25 mg/kg) and allopurinol (25 mg/kg) (cocktail group); 4) PRP and cocktail (full-compound); or 5) saline (control). The latter two groups received daily oral ibuprofen (25 mg/kg) for 7 days and allopurinol (25 mg/kg) for 30 days, postoperatively. Hemodynamic and echocardiographic studies were carried out at baseline, immediately after infarction and at end-point. Eight weeks after MI, the full-compound group had better LV fractional area change, ejection fraction and smaller LV dimensions than the control group. Also, dp/dtmax was significantly higher in the full-compound group when the heart rate increased from 100 bpm to 160bpm in stress tests. Blood vessel density was higher in the full-compound group, compared to the other treatment groups. CONCLUSIONS: A combination of PRP, anti-oxidant and anti-inflammatory factors with intramyocardial injection of hydrogel has the potential to structurally and functionally improve the injured heart muscle while attenuating adverse cardiac remodeling after acute myocardial infarction.

Modified carpentier's technique for Ebstein's anomaly repair.

OBJECTIVES: This retrospective study assesses the outcomes of a modified Carpentier's technique for Ebstein's anomaly repair in respect to functional and anatomical recovery of the right ventricle and tricuspid valve. PATIENTS AND METHODS: From August 2005 to December 2010, 52 patients with Ebstein's anomaly were operated in Hanoi Heart Hospital, Vietnam using the modified Carpentier's technique: (1) extensive mobilization of the tricuspid leaflet by detachment of the posterior, septal, and the adjacent part of the anterior leaflet; (2) longitudinal plication of the atrialized chamber and the right atrium to reconstruct the right ventricle and reduce the size of the dilated right atrium; (3) relocation of the anterior, posterior, and septal leaflets to the normal tricuspid annulus; and (4) tricuspid annuloplasty. RESULTS: Mean age was 20 years (3-49 years). Tricuspid regurgitation (in four-grade scale) was reduced from 3.72 ± 0.48 to 1.56 ± 0.48 (p < 0.01) and NYHA functional class was improved from 2.53 ± 0.53 to 1.14 ± 0.35 (p < 0.01). There was one hospital death (1, 95%) due to postoperative severe bleeding. There was no long-term mortality or reoperation after 42.4 months (17-81 months) follow-up. CONCLUSION: Satisfactory outcomes can be achieved with complete repair of Ebstein's anomaly using the modified Carpentier's technique.

Is continuation of antiplatelets until coronary artery bypass safe in Asians?

BACKGROUND: Controversies have arisen about the risks of discontinuing antiplatelets prior to coronary artery bypass grafting. METHODS: We retrospectively studied the effects of different strategies of antiplatelet discontinuation prior to coronary artery bypass on perioperative bleeding and major adverse cardiovascular events in Asian patients in a single center in Singapore. RESULTS: 402 patients were divided into 4 groups: group A had no antiplatelets before surgery; antiplatelets were stopped for 5-7 days in group B; 2-4 days in group C; and 0-1 day in group D. Compared to group B, group D had longer intensive care unit stays and more intraoperative transfusions of blood (p = 0.006) and blood products (p < 0.05). The 1-year major adverse cardiovascular event rate was higher in groups A and D (p = 0.027). Stopping antiplatelets within 24 h of surgery was one of multiple independent predictors of intraoperative transfusion but not the 1-year major adverse cardiovascular event rate. Patients on aspirin alone had less intraoperative transfusion of platelets and postoperative minor bleeding than those on combined therapy. CONCLUSION: Continuation of antiplatelets until 2 days before coronary artery bypass in Asian patients in our institution is unlikely to increase the risks of bleeding and perioperative transfusion. Taking antiplatelets within 24 h of surgery seems to be associated with a higher rate of 1-year major adverse cardiovascular events and bleeding, and an increased risk of blood product transfusion. Thirty-day and 1-year major adverse cardiovascular event rates were higher in patients without antiplatelet treatment.