Complex Structural Heart Disease Research Articles

Severe Pulmonary Hypertension in the Setting of Complex Structural Heart Disease

Pulmonary hypertension (pHTN) complicating structural heart disease leads to distinct diagnostic and management dilemmas. We present a case of severe pulmonary hypertension in the setting of perimembranous VSD and severe AS. 76 yo female with restrictive VSD and severe AS presented with heart failure. Cardiac findings included RV heave and AS murmur. TTE revealed normal EF with severe pHTN, severe RV dysfunction, and severe AS. Her perimembranous septum was aneurysmal, with systolic jet velocity of 4.5 m/s. There was no CAD. RHC demonstrated PAP of 96/38/57 mmHg, PVR of 7.2 WU, PCWP 23 mmHg, CI of 3.04, and Qp/Qs of 1.1. The PCWP and PVR indicated pre- and post-capillary pHTN due to longstanding AS. She was deemed inoperable and was high risk for TAVR given aortic annular continuity with the VSD and ∼25% annular deficiency. There was concern that her elevated LVEDP was masking Eisenmenger physiology, and that relieving the AS may precipitate hypoxia. Balloon aortic valvuloplasty (BAV) was performed as bridge to decision. This enabled assessment of the integrity of the aortic annulus, the pulmonary pressure response to LV unloading, and development of right to left shunting after a decrease in LVEDP. Successful BAV was performed, and the patient was discharged. Following improvement in both PA pressures and her symptoms, a TAVR was offered. A self-expanding valve was selected to minimize risk of annular rupture. After successful deployment, her PAP were 78/42/54 and PCWP 23. She was diuresed and discharged. Our case highlights important points in management of such complex patients with pHTN. Careful evaluation of hemodynamics is paramount in guiding decision making. The preserved PAPi with minimal shunting suggested the VSD was not significantly contributing to the severe pHTN. Additionally, BAV plays an important role as a bridge to determine potential response to TAVR. Although patients with WHO II pHTN can develop an irreversible pre-capillary component, such assessment can only be made following durable reduction in LVEDP. Lastly, interdisciplinary patient care is essential. Successful management of our patient required input from a multidisciplinary team consisting of pulmonology, structural cardiology, critical care cardiology and heart failure.

Influence of hospital volume and outcomes of adult structural heart procedures.

Hospital volume is regarded amongst many in the medical community as an important quality metric. This is especially true in more complicated and less commonly performed procedures such as structural heart disease interventions. Seminal work on hospital volume relationships was done by Luft et al more than 4 decades ago, when they demonstrated that hospitals performing > 200 surgical procedures a year had 25%-41% lower mortality than those performing fewer procedures. Numerous volume-outcome studies have since been done for varied surgical procedures. An old adage "practice makes perfect" indicating superior operator and institutional experience at higher volume hospitals is believed to primarily contribute to the volume outcome relationship. Compelling evidence from a slew of recent publications has also highlighted the role of hospital volume in predicting superior post-procedural outcomes following structural heart disease interventions. These included transcatheter aortic valve repair, transcatheter mitral valve repair, septal ablation and septal myectomy for hypertrophic obstructive cardiomyopathy, left atrial appendage closure and atrial septal defect/patent foramen ovale closure. This is especially important since these structural heart interventions are relatively complex with evolving technology and a steep learning curve. The benefit was demonstrated both in lower mortality and complications as well as better economics in terms of lower length of stay and hospitalization costs seen at high volume centers. We present an overview of the available literature that underscores the importance of hospital volume in complex structural heart disease interventions.

The Learning Curve in Percutaneous Repair of Paravalvular Prosthetic Regurgitation: An Analysis of 200 Cases

This study sought to assess the learning curve for percutaneous repair of paravalvular prosthetic regurgitation. Percutaneous repair of prosthetic paravalvular regurgitation is a complex procedure. There is a paucity of data on the professional experience and tools needed to achieve optimal clinical outcomes. We examined the chronological experience of 200 patients (age 66 ± 13 years; 57% men) who underwent percutaneous closure of paravalvular prosthetic regurgitation at our institution. A sequence number of the patient was assigned as a continuous variable for analysis. A total of 243 paravalvular defects (74% mitral; 26% aortic) were treated. Device delivery was successful in 92% with an average procedural time of 139 ± 47 min. The 30-day rate of major adverse cardiovascular events was 7%. With increased case experience and adoption of dedicated imaging and catheter techniques, there were decreases in procedural time, fluoroscopy time, contrast volume administered, length of hospital stay, and major adverse cardiovascular events. Procedural success remained unchanged throughout the experience. The predominant reason for procedural failure was prosthetic leaflet impingement, which accounted for 9 of 21 failed cases. In this single-center experience, there was evidence of a learning curve that occurred with the adoption of dedicated techniques for catheter delivery and echocardiographic imaging. In experienced operators, the potential for prosthetic leaflet impingement is the predominant limitation of the procedure. These data have implications for physician training and performance in complex structural heart disease interventions.

Atrial Tachycardia Originating from the Atrial Septum in a Patient with Dextrocardia and Complex Structural Heart Disease

We report a case with dextrocardia, corrected transposition of the great arteries. He also had an atrial septum defect (ASD) with patch repair. Activation map showed a centrifugal activation from a focal origin on the systemic lower left atrial ASD patch. Ablation of the origin can terminate the atrial tachycardia.

Percutaneous Transvenous Melody Valve-in-Ring Procedure for Mitral Valve Replacement

The purpose of this study was to demonstrate the feasibility of percutaneous transvenous mitral valve-in-ring (VIR) implantation using the Melody valve in an ovine model. The recurrence of mitral regurgitation following surgical mitral valve (MV) repair in both adult and pediatric patients remains a significant clinical problem. Mitral annuloplasty rings are commonly used in MV repair procedures and may serve as secure landing zones for percutaneous valves. Five sheep underwent surgical MV annuloplasty (24 mm, n = 2; 26 mm, n = 2; 28 mm, n = 1). Animals underwent cardiac catheterization with VIR implantation via a transfemoral venous, transatrial septal approach 1 week following surgery. Hemodynamic, angiographic, and echocardiographic data were recorded before and after VIR. VIR was technically successful and required <1 h of procedure time in all animals. Fluoroscopy demonstrated securely positioned Melody valves within the annuloplasty ring in all animals. Angiography revealed no significant MV regurgitation in 4 and moderate central MV regurgitation in the animal with the 28-mm annuloplasty. All animals demonstrated vigorous left ventricular function, no outflow tract obstruction, and no aortic valve insufficiency. This study demonstrated the feasibility of a purely percutaneous approach to MV replacement in patients with preexisting annuloplasty rings. This novel approach may be of particular benefit to patients with failed repair of ischemic mitral regurgitation and in pediatric patients with complex structural heart disease.

Atrial Tachycardia in a Patient with Complex Structural Heart Disease

A 53-year-old male patient with dextrocardia and situs viscera inversus, a congenitally corrected transposition of the great arteries (c-TGA), and atrial septum defect (ASD), secundum type, post patch repair was referred to our laboratory for treatment of frequent episodes of arrhythmia. In the previous fourteen years, the patient had experienced multiple supraventricular tachycardias (SVTs), which were successfully ablated 14, 12, and 2 years prior, respectively. This time in the electrophysiology laboratory, a narrow QRS tachycardia (cycle length=380 msec) was induced by right ventricular and right atrial incremental pacing with concentric activation. A bi-atrial activation map was constructed using a NavX system (St. Jude Medical, St. Paul, MN, USA) via a transseptal procedure to approach the systemic left atrium, which showed a centrifugal activation from a focal origin with mapped cycle length 121 ms (32% of the tachycardia cycle length) on the systemic high left atrial septum where a large low voltage zone was observed. The bipolar electrograms at the origin of the focal atrial tachycardia (AT) demonstrated fractionated and low-amplitude potentials. Successful ablation was carried out at the AT origin resulting in the non-inducibility of the AT. No recurrence of the tachycardia was observed during one year of follow-up.

Initial Experience With a Miniaturized Multiplane Transesophageal Probe in Small Infants Undergoing Cardiac Operations

There has been reluctance to use intraoperative transesophageal echocardiography (TEE) in small infants. We assessed the utility and safety of a new miniaturized multiplane micro-TEE probe in small infants undergoing cardiac operations. Hemodynamic and ventilation variables were prospectively recorded before and after micro-TEE insertion and removal in infants weighing 5 kg or less undergoing cardiac operations. The study included 42 patients with a mean weight of 3.6 +/- 0.9 kg (range, 1.7 to 5 kg). All probe insertions were successful. There were no complications or clinically significant changes in hemodynamic or ventilation variables. Information provided by TEE resulted in surgical revision in 6 of the 42 patients. The micro-TEE provides high quality, useful diagnostic images without hemodynamic or ventilation compromise in small infants undergoing cardiac operations. This advance is important with the growing trend towards complete repair of complex structural heart disease in small infants.

Dyslipidemia, inflammation and dialysis outcomes: what we know now

The limited prognosis of patients with chronic kidney disease starts when renal function begins to decline. Available interventions did not prove their efficacy. Treatment of dyslipidemia and inflammation by statins was shown to be effective in post-hoc subgroup analyses of large-scale randomized controlled trials in patients with chronic kidney disease stages 2 and 3. So far, randomized controlled trials in dialysis patients (HEMO, ADEMEX, 4D study) and after kidney transplantation (ALERT study) have produced so-called 'negative results'. It is most likely that these trials had limited power to prove the primary hypothesis. It is also probable that cardiac disease in renal patients changes its character from a vascular atherosclerotic to a more complex structural heart disease in combination with stiff arteries (arteriosclerosis). Clinically, this leads to a high proportion of sudden cardiac deaths: of 270 cardiac deaths in the 4D trial, 160 were of sudden cardiac origin. A complex pathogenetic process and a number of new emerging cardiovascular disease risk factors in the setting of high-grade inflammation/infection are proposed as being responsible. This review focuses on outcome variables in diabetic hemodialysis patients with special focus on risk factors such as inflammation and dyslipidemia.

Laterality disturbances

One of the earliest, and most crucial, steps in cardiac morphogenesis is looping of the primitive heart tube. This process provides the spatial context for all future steps in heart development, and defects in cardiac loop formation result in complex structural heart disease. Loop formation is also one of the first visible asymmetries along the left-right body axis, and as such is dependent upon the development of the entire embryonic left-right axis. Formation of the left-right body axis is a developmental process, that, like the formation of the anteroposterior and dorsoventral axes, is programmed by multiple genetic steps. It is also a process that is essential and unique to vertebrate development. Therefore, an understanding of the development of left-right asymmetry at the genetic and molecular level will greatly aid in the understanding of the etiology of this complex group of congenital heart defects.

Sotalol for refractory arrhythmias in pediatric and young adult patients: Initial efficacy and long-term outcome

Sotalol is an antiarrhythmic medication that has properties of both a β-blocker and a class III agent and has been used safely and effectively to treat arrhythmias of multiple mechanisms in pediatric patients. The purpose of this study was to review our institutional experience with sotalol in 45 patients with refractory arrhythmias and determine their long-term outcome. Patients responded to sotalol with 80% efficacy and a 22% incidence of adverse side effects. The mean sotalol dose was 116 mg/m 2/day, and the average duration of therapy was 15.2 months. In spite of 80% efficacy, only 22% of patients remained on sotalol long-term. Sotalol was discontinued most commonly for either spontaneous resolution of disease or definitive cure by radiofrequency ablation. Other reasons for discontinuation of effective therapy included adverse side effects and arrhythmia control with either an antitachycardia pacemaker or another medication. One patient died while taking sotalol, but this case was considered a failure of treatment rather than an adverse side effect. Of the patients who still receive therapy, several have complex structural heart disease and require a combination of therapies, including sotalol, for adequate rhythm control.