Pulmonary Valve Replacement via Left Thoracotomy as an Alternative to Resternotomy

Most patients with repaired tetralogy of Fallot (TOF) survive to adulthood and suffer from residual right ventricular pathology, mostly pulmonary regurgitation. Pulmonary valve replacement (PVR) is a procedure of choice to alleviate right ventricular dilatation and pulmonary regurgitation. Resternotomy is the standard approach for PVR in patients who have undergone TOF repair. However, these patients require multiple reoperations during their lifetime. We performed minimally invasive redo PVR through left mini-thoratocomy in 2 patients who had previously undergone TOF repair through sternotomy.

Preoperative distal aortic diameter is a significant predictor of late aorta-related events after endovascular repair for chronic type B aortic dissection

OBJECTIVES

Long-term therapeutic effects of thoracic endovascular aortic repair (TEVAR) for chronic type B aortic dissection remain controversial. This study aimed to evaluate the possible predictors of late aortic rupture and re-interventions after TEVAR.

METHODS

We retrospectively reviewed the operative outcomes of 40 patients who underwent TEVAR for chronic type B aortic dissection at Kyushu University Hospital. During a mean follow-up period of 39.2 months, we assessed aortic morphology via computed tomography and then employed a multivariable Cox regression analysis in an attempt to identify the predictors of late aorta-related events.

RESULTS

The early success rate of TEVAR was 100%. During the follow-up, however, three patients died from aortic rupture. Eight patients required aortic re-intervention, including thoraco-abdominal aortic graft replacement, repeated TEVAR, total arch replacement and EVAR. Multivariable Cox regression analysis revealed that the preoperative maximum distal aortic diameter was a significant predictor of late aorta-related events. The cutoff value of the distal aortic diameter was 40 mm. Freedom from aorta-related events was 94.6% at 1 year and 78.3% at 3 years. The survival rate was not significantly different despite the re-intervention.

CONCLUSIONS

TEVAR is an effective treatment for chronic type B dissection, with acceptable mid-term results. The preoperative distal aortic diameter is a significant risk factor for late aorta-related events. When the maximum distal aortic diameter is ≥ 40 mm, a therapeutic strategy should be developed taking into consideration the possible need for aortic re-intervention.

Pneumopericardium suggesting left ventricular assist device-related gastrointestinal complication

We report an uncommon case of ventricular assist device-related infection and resultant fistula formation into the gastrointestinal tract. A 69-year-old man, who had undergone implantation of a HeartMate II 1 year earlier secondary to ischemic cardiomyopathy, presented to our hospital with a high fever. Computed tomography showed unusual gas collection around the heart apex (i.e., pneumopericardium), which had not been detected before. The patient developed sudden melena with fresh blood without abdominal symptoms 1 month after beginning antibiotic therapy. Emergent colonoscopy showed that the HeartMate II strain relief of the inflow conduit had penetrated the transverse colon. We immediately performed laparoscopy-assisted left-sided hemicolectomy and found intraoperatively that a fistula had formed between the splenic flexure and the pericardial cavity. Subsequently, the HeartMate II system was totally explanted and replaced with an Impella 5.0 for alternative hemodynamic support. In our patient, pneumopericardium might have been an early sign of a hidden gastrointestinal complication. Our experience is a caution for clinicians who manage patients with ventricular assist device support via the apex.

Single-Stage Hybrid Arch Repair for Patients with Shaggy Aorta

Operating on extended arch aneurysms that contain severe atherosclerotic plaques is difficult. In such cases, the incidence of intraoperative multiple embolization is very high. We applied single-stage hybrid arch repair, which involved ascending aorta replacement and debranching of arch vessels, consecutively with endovascular repair for two patients. This technique was developed to prevent embolization of atherosclerotic plaques during cardiopulmonary bypass, and abrasion of the plaques during thoracic endovascular repair. Both patients recovered without embolic complications.

Flow Pattern of Outflow Graft is Useful for Detecting Pump Thrombosis in a Patient with Left Ventricular Assist Device

Pump thrombosis (PT) is a serious complication after continuous-flow left ventricular assist device (LVAD) implantation. To detect PT, echocardiographic ramp test using left ventricular end-diastolic diameter (LVEDD) is known to be useful. However, this method has several limitations. In this study, we propose an alternative novel ramp test using the flow velocity of outflow graft (OG). A 46-year-old man underwent continuous-flow LVAD (HeartMate II, Abbott Laboratories, Lake Forest, IL, USA) implantation for advanced heart failure due to idiopathic dilated cardiomyopathy. About 2 years after implantation, he suffered from hemolysis and symptoms of heart failure, and PT was strongly suspected. The change in LVEDD was minimal with increase in pump speed (-0.06 cm/400 rotations per minute (rpm)), suggesting PT. The systolic to diastolic velocity (S/D) ratio of OG flow, which we proposed as a new indicator of PT, also showed minimal change (-0.07/400 rpm). His clinical symptoms improved with anticoagulation therapy, and the changing slope of the S/D ratio dramatically improved to -0.92/400 rpm. Although its consistency should be verified in many other cases, this novel method can be useful for detecting PT and evaluating its clinical course.

Implication of Preoperative Existence of Atrial Fibrillation on Hemocompatibility-Related Adverse Events During Left Ventricular Assist Device Support

BACKGROUND

Hemocompatibility-related adverse events (HRAEs) are substantial issues in patients with left ventricular assist devices (LVADs). Atrial fibrillation (AF) is associated with worse prognosis in patients with heart failure (HF), but its effect on HRAEs following LVAD implantation remain uncertain.Methods and Results:Data from the Japanese Mechanically Assisted Circulatory Support registry of consecutive patients who received HeartMate II LVADs and were followed for 1 year were retrospectively reviewed. Among 190 patients, 23 had AF and 167 had sinus rhythm. The AF group had comparable baseline characteristics with the non-AF group except for their higher age (53 vs. 42 years, P<0.001). Following LVAD implantation, most cases of AF (73%) persisted. Antiplatelet therapy, anticoagulation therapy, and LVAD speed following LVAD implantation were comparable between groups (P>0.05 for all). The 1-year survival free from HRAEs was comparable between groups (83% vs. 76%, P=0.52). Event rates of the breakdown of HRAEs were comparable between groups except for a relatively higher rate of surgically managed pump thrombosis in the AF group (0.16 vs. 0.04, incidence rate ratio 3.75, 95% confidence interval 0.87-16.1, P=0.075). These trends still remained with propensity score-matched comparison.

CONCLUSIONS

Existence of AF had no effect on the development of HRAEs following LVAD implantation. The need to aggressively treat AF before or after LVAD implantation needs further investigation.

Comparison of cardiac energetics after transcatheter and surgical aortic valve replacements

OBJECTIVES

The effect of transcatheter aortic valve replacement (TAVR) on cardiac energetics has not been described. We compared changes in cardiac energetics after TAVR with those after surgical aortic valve replacement (SAVR).

METHODS

We retrospectively estimated end-systolic elastance (Ees) and effective arterial elastance (Ea) using blood pressure and left ventricular (LV) volume obtained from echocardiography. LV efficiency [ventriculoarterial coupling (Ea/Ees) and the stroke work to pressure-volume area ratio (SW/PVA)] was calculated. Measurements were taken before, 1 week after and 1 year after bioprosthetic aortic valve replacement (TAVR, n = 56; SAVR, n = 61) in patients with severe aortic stenosis and preserved ejection fraction.

RESULTS

Patients with TAVR had a lower aortic valve pressure gradient and larger stroke volume 1 week after the procedure than those with SAVR. Ea was more markedly decreased, and LV efficiency was significantly improved 1 week after TAVR (SW/PVA 68.1% ± 8.4% to 72.0% ± 8.5%, P < 0.001), but LV efficiency was unchanged 1 week after SAVR (SW/PVA 70.1% ± 7.4% to 69.1%  ±  8.0%). LV efficiency was improved 1 year after both procedures (SW/PVA 75.5% ± 6.1% in TAVR; 74.7% ± 6.4% in SAVR).

CONCLUSIONS

TAVR decreases the transvalvular pressure gradient further without deteriorating stroke volume in the early postoperative period, which is accompanied by early improvement in afterload and LV efficiency compared with SAVR. Improvement in LV efficiency at mid-term follow-up is satisfactory after both procedures.

[Congenitally Corrected Transposition of the Great Arteries( TGA) in Adult]

OBJECTIVES

In patients with congenitally corrected transposition of the great arteries( cc-TGA), the morphological right ventricle (RV) sustains the systemic circulation and is frequently associated with progressive tricuspid regurgitation and declining RV function.

METHODS

Thirty-four patients with cc-TGA and systemic RV were enrolled in this retrospective study to examine long-term outcome.

RESULTS

Age was averaged 38.5 years. Associated cardiac anomaly included ventricular septal defect (VSD) and pulmonary stenosis in 18, VSD in 4. Twelve had no associated cardiac defect. The physiologic repair was performed in 22 patients at the mean age of 7.8 years old. Reoperation was frequent including tricuspid valve surgery in 11 and left ventricle( LV)-pulmonary artery( PA) conduit replacement in 10. Five patients needed pacemaker implantation due to heart block. Aortic insufficiency was a relatively common finding and aortic valve replacement was performed in 4. All but 2 patients were better than New York Heart Association (NYHA) class Ⅱ. One needed implantable ventricular assist device implantation and the other underwent heart transplantation.

CONCLUSIONS

Long-term outcome for patients with cc-TGA was satisfactory. Frequent reoperations including tricuspid valve surgery and LV-PA conduit replacement were required. Further careful follow-up will be needed to detect the progression of RV dysfunction and tricuspid and aortic insufficiency.

HeartMate II Implantation Via Single Incisional Ministernotomy in a Small Young Woman

We report a successful case of less invasive implantation of a HeartMate II in a small young woman. A 34-year-old woman, who developed refractory heart failure associated with chronic myocarditis, underwent implantation of a HeartMate II via T-shaped ministernotomy without any additional incisions. This approach has several unique advantages: all of the procedures can be operated in the same view in the usual fashion with minor modifications; some optional procedures can be easily added during the operation if necessary. To confirm the feasibility and versatility of this approach, we assessed the postimplant pump position by the radiographic parameters. The radiographic assessment showed that those parameters were not significantly different than those in our other normal body-sized patients. There were no adverse events associated with HeartMate II implantation during her follow-up. We consider that this approach has the feasibility and versatility, and can be an alternative approach in cases where the conventional approach is inappropriate for some reason.

Pectoral Muscle Atrophy After Axillary Artery Cannulation for Aortic Arch Surgery

To investigate postoperative pectoral atrophy in 141 patients undergoing aortic arch surgery involving bilateral axillary artery cannulations with side grafts. The depth from the skin to the axillary artery surrounding the thoracoacromial artery (zone 1), and the thicknesses of pectoralis major (zone 2) and pectoralis minor (zone 3) were measured by computed tomography before surgery, at 1 and 6 months after surgery, and at the most recent follow-up assessment (PostT2) (mean = 41 months, range 11-75 months). Based on the median value (47.4 mm) of zone 1, the preoperative pectoral thickness was categorized into 2 groups: pectoral thickness >47.4 mm (thick group) and ≤47.4 mm (thin group). Mean changes in the pectoral thickness from baseline were evaluated using the longitudinal mixed-effects model. Forty-three of 110 patients underwent total arch replacements and extra-anatomical bypasses for left subclavian artery anastomoses. In 3 patients, axillary artery grafts became infected. There was no obvious harm associated with muscle wasting. Mean changes from baseline in zones 1, 2, and 3 showed significant declines at PostT2 (-13.40 ± 9.73 mm [P < 0.0001], -7.00 ± 5.23 mm [P < 0.0001], and -7.23 ± 6.42 mm [P < 0.0001], respectively). In the thick group, the progression of pectoral atrophy in zones 1 and 3 was significantly more than that of the thin group (P < 0.0001 for both zones). Postoperative pectoral atrophy progressed rapidly. The preoperative pectoral size might be of no use in the prevention of pectoral atrophy. Further investigation to prevent the pectoral atrophy is needed.

Pediatric Biventricular Assist Device for Myocarditis and Complicated Left Ventricular Thrombus

An 8-year-old girl presenting with fulminant myocarditis and cardiogenic shock underwent peripheral extracorporeal membrane oxygenation. She was switched to central extracorporeal membrane oxygenation because of inadequate venous drainage, and an echocardiogram showed left ventricular (LV) thrombus. She underwent removal of the LV thrombus with LV venting. An echocardiogram showed LV thrombus again 2 days later. The LV thrombus was again removed, and a biventricular assist device support was initiated to avoid further thrombus formation. The patient was completely weaned from mechanical circulatory support after 7 days. She recovered fully without any neurologic deficit.

Omental and deep inferior epigastric artery perforator flap coverage after heart transplantation to manage wide left ventricular assist device exposure with pocket infection

Infection is a serious potential complication after left ventricular assist device (LVAD) implantation. In general, infection of the device pocket, with device exposure, should be managed by early device removal and heart transplantation. However, because of the small number of donors in Japan, accelerating access to heart transplantation is often difficult and the LVAD can be widely exposed during the waiting period. We report our experience of successful heart transplantation in a patient with a widely exposed LVAD with pocket infection. A 48-year-old man suffered from heart failure due to idiopathic dilated cardiomyopathy. An LVAD was implanted, but postoperative infection led to blood pump exposure. Heart transplantation was performed 4 months after LVAD exposure, at which time the epigastric skin defect measured 14 × 8 cm. The skin defect could not be closed after heart transplantation, so it was covered by an omental flap with split-thickness skin grafts. 7 days postoperatively, the peritoneal suture broke and the intestinal tract prolapsed outside the body. Reintroduction of the prolapsed intestinal tract and deep inferior epigastric artery perforator (DIEP) flap coverage of the omental flap were performed. The postoperative course was uneventful. There have been no reports of the management of wide skin defects in the presence of infection when heart transplantation is performed. Omental flap placement was useful for controlling long-lasting infection. An omental flap placed in a patient with a wide epigastric skin defect should be covered by durable skin flap, such as a DIEP flap, to avoid intestinal prolapse.

Axillo-iliac artery bypass for recurrent aortic coarctation to reduce cardiac afterload

A 13-year-old girl, who had undergone interrupted aortic arch repair with an 8-mm graft as a neonate and Fontan completion in childhood, developed ventricular fibrillation due to long-QT syndrome. Cardioverter defibrillator implantation was planned. Preoperative catheterization showed a 45-mmHg aortic pressure gradient and ventricular end-diastolic pressure of 11 mmHg. This indicated that recurrent coarctation had adversely affected ventricular function. After consideration of the patient's age, symptoms and anatomical/surgical complexities, axillo-iliac bypass with cardioverter defibrillator implantation was performed. Postoperative ventricular end-diastolic pressure was 6 mmHg. Axillo-iliac bypass is a surgical option for coarctation that can reduce cardiac afterload.

[The Role of Extracorporeal Ventricular Assist Device is Changing in the Era of Implantable Ventricular Assist Device]

In the era of implantable ventricular assist device (VAD), the role of extracorporeal VAD is changing. The extracorporeal VAD was ever the mainstream of treatment for severe heart failure. Now, it is mainly applied to patients with severe cardiogenic shock. Recently the centrifugal pump available for cardiopulmonary bypass system has been often used as the extracorporeal VAD because of its simplicity of management. Although the implantable VAD plays the pivotal role for bridge to transplantation since its clinical introduction in 2011, the extracorporeal VAD still has the important role for end-stage heart failure and cardiogenic shock. We have experienced 47 cases of the extracorporeal VAD until now. Here, based on our experience, we describe the "past and present" role of the extracorporeal VAD and mention the future aspect of the extracorporeal VAD.