A tissue-silicone integrated simulator for right ventricular pulsatile circulation with severe functional tricuspid regurgitation.

There is a great demand for development of a functional tricuspid regurgitation (FTR) model for accelerating development and preclinical study of tricuspid interventional repair devices. This study aimed to develop a severe FTR model by creating a tissue-silicone integrated right ventricular pulsatile circulatory simulator. The simulator incorporates the porcine tricuspid annulus, valve leaflets, chordae tendineae, papillary muscles, and right ventricular wall as one continuous piece of tissue, thereby preserving essential anatomical relationships of the tricuspid valve (TV) complex. We dilated the TV annulus with collagenolytic enzymes under applying stepwise dilation, and successfully achieved a severe FTR model with a regurgitant volume of 45 ± 9 mL/beat and a flow jet area of 15.8 ± 2.3 cm2 (n = 6). Compared to a normal model, the severe FTR model exhibited a larger annular circumference (133.1 ± 8.2 mm vs. 115.7 ± 5.5 mm; p = 0.009) and lower coaptation height (6.6 ± 1.0 mm vs. 17.7 ± 1.3 mm; p = 0.003). Following the De-Vega annular augmentation procedure to the severe FTR model, a significant reduction in regurgitant volume and flow jet area were observed. This severe FTR model may open new avenues for the development and evaluation of transcatheter TV devices.

Repairable ex vivo model of functional and degenerative mitral regurgitation.

OBJECTIVES: Transcatheter mitral valve repair is an emerging alternative to the surgical repair. This technology requires preclinical studies to assess efficacy in mitigating mitral regurgitation (MR). However, ex vivo MR models are not established. We developed 2 novel repairable models, functional and degenerative, which can quantitatively assess regurgitation and effect of intervention. METHODS: We used porcine mitral valves and a pulsatile flow circulation system. In the functional MR model, the annulus was immersed in 0.1% collagenase solution and dilated using 3D-printed dilators. To control the regurgitation grade, the sizes of the dilator and silicone sheet in which the valve was sutured to were adjusted. Chordae of P2 were severed in the degenerative model, and the number of severed chordae was adjusted to control the regurgitation grade. Models were repaired using the edge-to-edge or artificial chordae technique. RESULTS: The mean regurgitant fraction of the moderate-severe functional and degenerative models were 47.9% [standard deviation (SD): 2.2%] and 58.5% (SD: 8.0%), which were significantly reduced to 28.7% (SD: 4.4%) (P < 0.001) and 26.0% (SD: 4.4%) (P < 0.001) after the valve repair procedures. Severe functional model had a mean regurgitant fraction of 59.4% (SD: 6.0%). CONCLUSIONS: Both functional and degenerative models could produce sufficient MR levels that meet the interventional indication criteria. The repairable models are valuable in evaluating the efficacy of valve repair procedures and devices. The ability to control the amount of regurgitation enhances the versatility and reliability of these models. These reproducible models could expedite the development of novel devices.

Double-leaflet Technique for Mitral Regurgitation With Small or Tethered Posterior Leaflet.

Small leaflets make mitral valve repair procedures challenging. Our double-leaflet technique creates a new autologous pericardial leaflet attached to the papillary muscle, annuloplasty ring, and neighboring scallops above the small or tethered posterior leaflet. This simple additional technique provides deep coaptation after mitral valve repair for both degenerative and functional mitral regurgitation with the small or tethered posterior leaflet.

Delayed surgery after mechanical circulatory support for ventricular septal rupture with cardiogenic shock.

OBJECTIVES: The effectiveness of delayed surgery for ventricular septal rupture (VSR) following myocardial infarction (MI) in patients with cardiogenic shock remains unknown. We aimed to investigate the outcomes of delayed surgery following mechanical circulatory support for patients in cardiogenic shock after VSR. METHODS: We reviewed 8 patients with post-MI VSR and cardiogenic shock who underwent delayed surgery at our institution between July 2015 and November 2017. Surgery was delayed until haemodynamic stabilization and improved organ ischaemia were achieved by initiating intra-aortic balloon pumping with or without veno-arterial extracorporeal membrane oxygenation (ECMO). We investigated the operative mortality, morbidity and late survival. RESULTS: All 8 patients had preoperative intra-aortic balloon pump support, and 5 had additional veno-arterial ECMO support. Emergency repair was successfully avoided in all cases. The median time from the onset of MI to operation was 7.1 (3.7-9.9) days, and that from the diagnosis of VSR to operation was 1.9 (1.3-2.3) days. The operative mortality was 12.5%, and complications related to mechanical circulatory support occurred in 1 case (12.5%). The 2-year survival rate was 62.5%. CONCLUSIONS: A combination of preoperative mechanical circulatory support and delayed surgery may improve the outcomes of patients with post-MI VSR, which was complicated by cardiogenic shock. The key to a better surgical outcome may be delaying the surgery for improving end-organ perfusion. This requires further investigation, especially for determining the optimal duration of support.

Outcomes of Extended Endovascular Aortic Repair for Aorto-Iliac Aneurysm with Internal Iliac Artery Occlusion.

Objective: Patients of aorto-iliac aneurysms who undergo endovascular aortic repair (EVAR) require internal iliac artery (IIA) occlusion with coil embolization and its coverage with the stent graft to prevent type II endoleak after extending the endograft into the external iliac artery. However, it has become well recognized that IIA occlusion cause buttock claudication and other various sequelae due to pelvic ischemia. We retrospectively analyzed IIA occlusion outcomes. Methods: From October 2008 to February 2015, 71 patients with aorto-iliac aneurysms underwent IIA occlusion prior to EVAR. The relationship between pelvic circulation and symptom of pelvic ischemia was studied. Results: Buttock claudication occurred in 17 patients (22.9%) of all. Eight patients (14.8%) in unilateral IIA occlusion group (54 patients) and nine patients (52.9%) in bilateral IIA group (17 patients) had sequelae of claudication. The sacrifice of the communication of superior gluteal artery (SGA) and inferior gluteal artery (IGA) led to buttock claudication in 18 (64.3%) of 28 limbs. Instead, only 4 of 60 limbs had buttock claudication, when we preserved the communication between SGA and IGA. In all patients, staged treatment of aorto-iliac aneurysms with IIA occlusion and EVAR were done successfully without pelvic ischemic complications except for buttock claudication, and postoperative CT scanning showed no endoleakage. Conclusion: IIA occlusion prior to EVAR is recognized as a safe and reasonable strategy. It is emphasized that preservation of the communication of SGA and IGA is important to prevent buttock claudication. (This is a translation of Jpn J Vasc Surg 2016; 25: 240-245.).