Comparing the Host Reaction to CorMatrix and Different Cardiac Patch Materials Implanted Subcutaneously in Growing Pigs.

BACKGROUND: Comparing the structural changes, and local host reactions to CorMatrix (CorMatrix Cardiovascular Inc., Roswell, Georgia, United States) and different biomaterials implanted subcutaneously in growing pig model. METHODS: Four pigs harboring implanted patches of CorMatrix, Vascutek porcine pericardium (Vascutek; Scotland, United Kingdom), SJM bovine pericardium (St. Jude Medical, Inc., Minnesota, United States), and Gore-Tex (W. L. Gore & Associates GmbH, Flagstaff, Arizona, United States) were studied for 1, 3, 6, and 12 months. The explants were examined histologically. RESULTS: CorMatrix showed gradual and consistent patch resorption and subsiding inflammatory and fibrosis process. Full scaffold degradation and replacement by mild fibrosis and subcutaneous tissue were seen by 1 year. Xenopericardial patches remained intact, and the initially severe inflammatory and fibrotic reactions reduced gradually to moderate fibrosis and chronic inflammation. Gore-Tex showed foreign body reaction. CONCLUSIONS: Patches were biotolerated by pigs. Xenopericardial patches elicited encapsulating fibrosis and no remodeling. CorMatrix resorbs completely and degrades consistently without leaving residues. Lack of encapsulating fibrosis toward CorMatrix allows tissue ingrowth and matrix remodeling.

Experimental Aortic Valve Cusp Extension with CorMatrix in a Porcine Model.

Background We tested the feasibility of using porcine small intestinal submucosal extracellular matrix (CorMatrix) for aortic valve (AV) repair in porcine model examining its resorption and remodeling potential. Methods The non-coronary cusp was replaced with CorMatrix in four animals for 120 days. Valve function was assessed by echocardiography. Explants were examined by histology, immunohistochemistry, and collagen assessment. Results CorMatrix was almost totally replaced with tissue resembling the native cusp with a partial two-layer architecture. However, function was lost due to thickening and calcification. Conclusions Tested in high-pressure AV position in a pig model, CorMatrix degrades and remodels, but also loses function.

Pain, Quality of Life, and Clinical Outcomes after Robotic Lobectomy.

Background To evaluate pulmonary function, pain, and quality of life at midterm after robotic lobectomy performed in a single institution. Methods Sixty-five consecutive patients underwent robotic thoracic surgery over 32 months using a complete four-arm portal technique. Sixty-one patients underwent lobectomies predominantly for stage I non-small cell lung cancer. Pulmonary function tests were repeated at midterm follow-up. Pain and quality of life were evaluated during the follow-up on a subgroup of 39 patients, excluding the learning period. Results At a mean of 7-month follow-up, there was no significant difference in preoperative and midterm postoperative pulmonary function. A total of 62.5% of the patients reported a variable intensity of discomfort or pain at the surgical site, with a mean pain intensity score of 2.1 ± 1.4. Mean pain interference score were weak (1.8 ± 1.9), with patients with moderate pain reporting significantly higher pain interference scores than those with mild pain (p = 0.0025). Only one patient suffered from neuropathic-like pain. Quality of life was globally favorable and related to the pain level, with a significant interference on the physical component. Conclusion Robotic lobectomy does not appear to have an impact on midterm pulmonary function. Persistent postoperative pain is mild, nonneuropathic-like, with weak interference on daily activities. Quality of life is satisfactory but related to the pain level.

Calcific Degeneration of CorMatrix 4 Years After Bicuspidization of Unicuspid Aortic Valve.

We report the long-term outcomes of a 12-year-old boy who underwent bicuspidization of a severely stenotic unicuspid aortic valve with CorMatrix small intestinal submucosal extracellular matrix (CorMatrix Cardiovascular, Roswell, GA). CorMatrix supported favorable immediate surgical and echocardiographic outcomes and maintained stable growing functional dynamics for 2 years. At 52.5 months in situ, however, the valve failed with severe calcification, fibrosis, and retraction necessitating a redo operation. Reconstructive operations with CorMatrix are feasible, but this result questions its capacity for constructive remodeling in left-sided valve repair.

CorMatrix valved conduit in a porcine model: long-term remodelling and biomechanical characterization.

OBJECTIVES: Porcine small intestinal submucosa extracellular matrix (CorMatrix; CorMatrix Cardiovascular, Rosewell, GA) is a relatively novel tissue substitute used in cardiovascular applications. We investigated the biological reaction and remodelling of CorMatrix as a tri-leaflet valved conduit in a pig model. We hypothesized that CorMatrix maintains a durable architecture as a valved conduit and remodels to resemble surrounding tissues. METHODS: We fashioned the valved conduit using a 7 × 10 cm 4-ply CorMatrix sheet and placed it in the thoracic aorta of seven landrace pigs for 3, 4, 5 and 6 months. Biodegradation, replacement by native tissue, strength and durability were examined by histology, immunohistochemistry and mechanical testing. RESULTS: Four pigs, one per time frame, completed the study. The conduit lost its original architecture as a tri-leaflet valve due to cusp immobility, subsequent attachment to the wall segment and consequent maintenance of a thick arterial wall-like structure. Scaffold resorption was incomplete, with disorganized inconsistent spatial and temporal degradation even at 6 months. Fibrosis, scarring and calcification started at 4 months and chronic inflammation persisted. The partially remodelled scaffold did not resemble the aortic wall, suggesting impaired remodelling. Mechanical testing showed progressive weakening of the tissues over time, which were liable to breakage. CONCLUSIONS: CorMatrix is biodegradable; however, it failed to remodel in a structured and anatomical fashion in an arterial environment. Progressive mechanical and remodelling failure in this scenario might be explained by the complexity of the conduit design and the host's chronic inflammatory response, leading to early fibrosis and calcification.

Small intestinal submucosa extracellular matrix (CorMatrix®) in cardiovascular surgery: a systematic review.

Extracellular matrix (ECM) derived from small intestinal submucosa (SIS) is widely used in clinical applications as a scaffold for tissue repair. Recently, CorMatrix® porcine SIS-ECM (CorMatrix Cardiovascular, Inc., Roswell, GA, USA) has gained popularity for 'next-generation' cardiovascular tissue engineering due to its ease of use, remodelling properties, lack of immunogenicity, absorbability and potential to promote native tissue growth. Here, we provide an overview of the biology of porcine SIS-ECM and systematically review the preclinical and clinical literature on its use in cardiovascular surgery. CorMatrix® has been used in a variety of cardiovascular surgical applications, and since it is the most widely used SIS-ECM, this material is the focus of this review. Since CorMatrix® is a relatively new product for cardiovascular surgery, some clinical and preclinical studies published lack systematic reporting of functional and pathological findings in sufficient numbers of subjects. There are also emerging reports to suggest that, contrary to expectations, an undesirable inflammatory response may occur in CorMatrix® implants in humans and longer-term outcomes at particular sites, such as the heart valves, may be suboptimal. Large-scale clinical studies are needed driven by robust protocols that aim to quantify the pathological process of tissue repair.

Endovascular resection of the native aortic valve before transcatheter aortic valve implantation: state of the art and review.

Transcatheter aortic valve implantation was introduced into clinical practice in 2002 as a rescue approach in patients presenting with symptomatic severe aortic stenosis but not eligible for conventional aortic valve replacement. This technique allows implantation of a balloon expandable bioprosthesis without resection of the native aortic valve. Several complications are described as a consequence of the residual highly calcified valve being squeezed against the aortic wall by the stent of the implant. This can result in deformation of the metal stent and paravalvular leakage, risk of occlusion of the coronary ostia, or central and peripheral embolization of valvular debris. To avoid these complications, many authors suggest the possibility to resect and remove the native aortic valve before transcatheter aortic valve implantation. In this field, different authors have described possible techniques and different sources of energy to resect the calcified valve. In this article, we review the development of these experimental techniques and discuss future prospects in this field.

Surgical anatomy of the aortic root: implication for valve-sparing reimplantation and aortic valve annuloplasty.

BACKGROUND: To enhance the reproducibility of aortic valve-sparing reimplantation and annuloplasty, we analyzed the topographic relationship between the ventriculoaortic junction (VAJ), basal ring (BR), and sinotubular junction (STJ). The root base thickness is also quantified. METHOD: Fifty-eight fresh human aortic valves were analyzed. The root was dissected to the limit where the aortic wall terminates into the cardiac structures (VAJ). Root height was measured externally from the STJ to the VAJ and internally from the STJ to the BR defined as the plane passing through the cusps nadir. The root base thickness was measured at the BR and orthogonal to the internal wall; except at the right coronary sinus, where it was measured between the BR internally and the VAJ externally. Measurements were taken at the middle of the 3 sinuses and commissures. RESULTS: The VAJ is at the same level as the BR from the noncoronary sinus (-0.1 ± 0.9 mm) to the left coronary sinus (0.5 ± 1.3 mm); it is above the BR from the left/right commissure (4.6 ± 1.4 mm) to the right/non commissure (2.5 ± 1.6 mm). The external root height was highest at the non/left commissure (21.5 ± 2.6 mm) followed by the right/non commissure (19.2 ± 2.3 mm) then the left/right commissure (15.7 ± 2.2 mm) (P < .05). The mean root base thickness was 3.2 mm, ranging from 1 ± 0 mm at the left/non commissure to 6.2 ± 1.2 mm at the right coronary sinus (P < .001). CONCLUSIONS: The VAJ is not planar; it is above the level of the BR from the left/right to the right/non commissure. As a consequence, the external height of the non/left commissure is greater than the other 2 commissures. These findings should be taken into consideration when performing aortic valve-sparing reimplantation or external annuloplasty.

Aortic valve repair with patch in non-rheumatic disease: indication, techniques and durability†.

OBJECTIVES: To analyse the long-term outcomes of aortic valve (AV) repair with biological patch in patient with non-rheumatic valve disease. METHODS: From 1995 to 2011, 554 patients underwent elective (AV) repair; among them, 57 (mean age 45 ± 17 years) had cusp restoration using patch for non-rheumatic valve disease. Seven (12%) patients had unicuspid valve, 30 (53%) patients had bicuspid valve and 20 (35%) had tricuspid valve. Autologous pericardium was used in 26 patients (7 treated, 19 non-treated), bovine pericardium in 26, autologous tricuspid valve leaflet in 4 and aortic homograft cusp in 1. Patching was used to repair perforation (n = 20, 35%), commissural defect (n = 18, 32%), raphe repair (n = 17, 30%) or for cusp extension (n = 2, 3.5%). Echocardiographic and clinical follow-up was 98% complete and mean follow-up was 72 ± 42.5 months. RESULTS: No hospital mortality. At 8 years, overall survival was 90 ± 5% and freedom from valve-related death was 96 ± 3%. Two patients (3.5%) needed early reoperation for aortic regurgitation (AR); they underwent re-repair and the Ross procedure, respectively. Late reoperation was necessary in 9 patients (16%) for AR (n = 4), stenosis (n = 3) or mixed disease (n = 2). They had the Ross procedure (n = 6) or prosthetic valve replacement (n = 3) with no mortality. At 8 years, freedom from reoperation was 75 ± 9%. Freedom from reoperation was slightly higher in tricuspid compared with non-tricuspid valves (92 ± 7 vs 68 ± 11%, P = 0.18) and slightly higher for bovine (95 ± 5%) compared with autologous pericardium (73 ± 11%, P = 0.38), but differences were statistically not significant. In tricuspid valves, freedom from reoperation was higher in perforation repair compared with other techniques (100 vs 50 ± 35%, P = 0.02). In bicuspid valves, freedom from reoperation was similar between different repair techniques (P = 0.38). Late echocardiography showed AR 0-1 in 30 (53%) patients, AR 2 in 12 (21%) and no AR ≥ 3. Three patients presented a mean transvalvular gradient of 30-40 mmHg. Thromboembolic events occurred in 2 patients (0.6%/patient-year), bleeding events in 1 (0.3% /patient-year) and no endocarditis occurred. CONCLUSIONS: AV repair with biological patch is feasible for various aetiologies. The techniques are safe and medium-term durability is acceptable, even excellent for perforation repair in tricuspid valve morphology. Bovine pericardium is a good alternative to autologous pericardium.

How to perform valve sparing reimplantation in a tricuspid aortic valve.

Aortic valve sparing procedures are increasingly being used to treat aortic root pathologies. Reimplantation of the aortic valve, first described by Dr Tirone David, is a technically demanding procedure whose long-term results are critically dependent on perfect intraoperative restoration of valve anatomy and function. There exists significant variation in how this procedure is performed by different surgeons, which is likely contributory to the heterogeneity in reported results. We describe a systematic approach to aortic valve reimplantation procedure focusing on key technical aspects.