Transcatheter Mitral Valve-in-Valve Implantation in Pediatric Patients.

BACKGROUND: Transcatheter implantation of the Edwards Sapien 3 valve (Edwards Lifesciences, Irvine CA) within the bioprosthetic mitral valve (MV) is an established method of treatment in adults. However, it has not been well studied in the pediatric age group. METHODS: Transcatheter mitral valve-in-valve implantation was attempted in 4 symptomatic pediatric patients with a dysfunctional MV bioprosthesis implanted at an earlier stage due to severe MV stenosis or regurgitation. We reviewed our experience with MV implantation in this cohort. RESULTS: The mean age and weight of the patients at the time of the procedure were 11.4 years (range: 10-14 years) and 36 kg (range: 31-44 kg), respectively. The transmitral mean gradient dropped from a mean of 19.75 mm Hg (range: 15-22 mm Hg) to a mean of 1 mm Hg (range: 0-3 mm Hg) after the procedure. The mean fluoroscopy time was 55.25 minutes (range: 40-72 minutes), and the mean hospital length of stay was 4 days (range: 3-7 days). The patients' functional class improved from New York Heart Association class IV to class I during the follow-up period. CONCLUSIONS: Transcatheter mitral valve-in-valve implantation can be performed safely for dysfunctional bioprosthetic MVs in the pediatric age group with favorable early and midterm outcomes. This procedure offers a viable alternative in patients who have high surgical risk or are deemed unfit for conventional surgery. However, we still recommend a long-term study of this approach in a large cohort, multicentre study.

INTRODUCTION: L'implantation de la prothèse valvulaire Edwards Sapien 3 (Edwards Lifesciences, Irvine, CA) par cathéter dans la bioprothèse valvulaire mitrale (VM) est une méthode de traitement établie chez les adultes. Toutefois, cette méthode n'a pas fait l'objet d'études approfondies auprès d'enfants. MÉTHODES: Une tentative d'implantation valvulaire mitrale de type valve-in-valve par cathéter a été réalisée chez quatre enfants symptomatiques qui avaient une bioprothèse VM dysfonctionnelle implantée antérieurement en raison d'une sténose VM ou d'une régurgitation grave. Nous avons passé en revue notre expérience d'implantation VM auprès de cette cohorte. RÉSULTATS: L'âge et le poids moyens des patients au moment de l'intervention étaient respectivement de 11,4 ans (étendue : 10-14 ans) et de 36 kg (étendue : 31-44 kg). La moyenne du gradient moyen transmitral a baissé. Elle est passée de 19,75 mmHg (étendue : 15-22 mmHg) à 1 mmHg (étendue : 0-3 mmHg) après l'intervention. La durée moyenne de la fluoroscopie était de 55,25 minutes (étendue : 40-72 minutes), et la durée moyenne du séjour à l'hôpital était de quatre jours (fourchette : 3-7 jours). La classification fonctionnelle des patients selon la New York Heart Association a montré une baisse. Les patients sont passés de la classe IV à la classe I durant la période de suivi. CONCLUSIONS: L'implantation valvulaire mitrale de type valve-in-valve par cathéter peut être pratiquée de façon sûre chez les enfants porteurs d'une bioprothèse VM dysfonctionnelle dont les issues à court ou à moyen terme sont favorables. Cette intervention est une alternative viable pour ces patients dont le risque lié à l'intervention chirurgicale est élevé ou considérés inaptes à subir une intervention chirurgicale traditionnelle. Toutefois, nous recommandons encore une étude à long terme sur cette approche, voire une vaste étude multicentrique de cohorte.

A novel and simple technique for correction of posterior leaflet prolapse due to chordal elongation or rupture.

OBJECTIVE: The study objective was to evaluate the midterm results of a technique for correction of posterior leaflet prolapse without resection or use of artificial chordae. METHODS: From May 2009 to October 2013, 96 patients with isolated posterior leaflet prolapse (n=36) or bileaflet prolapse (n=60) with or without chordal rupture underwent posterior leaflet repair at the Prince Sultan Cardiac Center. The novel Uniscallop ("U") technique was used in 46 patients (group U), based only on scallop suture without resection or artificial chordae application. A conventional approach (quadrangular or triangular resection, focal sliding, artificial chordae) was adopted in the remaining 50 patients (group C). In both groups, the annulus was reshaped using a 40- or 50-mm-long band. Postoperative echocardiography was performed in all patients after a mean follow-up of 18±13 months in group U and 20±9 months in group C. RESULTS: There were no early or late deaths. No patients in either group showed systolic anterior motion. Both surgical strategies were successful in obtaining a significant reduction in mitral regurgitation grade. Left ventricular function was maintained, and tricuspid regurgitation grade was reduced overall. Moderate mitral regurgitation during follow-up developed in only 1 patient in group C, as the result of dehiscence of a plication stitch. CONCLUSIONS: Although the rationale for the use of the U technique is different from what is generally accepted, the midterm results of this approach are comparable to those obtained with more conventional techniques, remaining stable after a mean follow-up of 18 months.

Chordal cutting in ischemic mitral regurgitation: a propensity-matched study.

OBJECTIVE: The optimal surgical treatment of ischemic mitral regurgitation (MR) has not been well defined. Second-order chordal cutting (CC), in selected patients, can improve surgical outcomes. METHODS: From 2007 to 2011, 31 patients underwent CC for ischemic MR. The indication was the presence of increased tethering of the anterior leaflet, with a bending angle (BA) <145°. Patients with same echocardiographic characteristics were identified and propensity matched for age, ejection fraction (EF), MR grade, diameters, and BA. Only patients with preoperative and follow-up echocardiograms were included and divided into 2 groups of 26 patients each, CC and no-CC. RESULTS: Preoperatively, in the CC and no-CC groups, the age was 61 ± 9 and 62 ± 10 years, EF was 31% ± 5% and 29% ± 8%, MR grade (0-4) was 3.6 ± 0.6 and 3.3 ± 0.8, and diastolic and systolic dimension was 56 ± 7 and 43 ± 8 mm and 57 ± 11 and 44 ± 11 mm, respectively. The New York Heart Association class and BA was 2.7 ± 0.6 and 2.6 ± 0.7 and 137° ± 4° and 137° ± 6°, respectively. All patients underwent overreductive annuloplasty. In the CC group, second-order chords were cut using aortotomy. After a mean of 33 ± 15 months, the MR grade was 0.6 ± 0.6 and 1.1 ± 0.8 (P = .014) and the EF was 40% ± 5% and 35% ± 7% (P = .005) in the CC and no-CC groups, respectively. The corresponding diastolic and systolic diameters were 52 ± 5 and 38 ± 8 mm and 53 ± 11 and 41 ± 12 mm (P = NS). The modifications were significant only in the CC group (P = .022 and P = .029 for the diastolic and systolic dimensions, respectively). The corresponding New York Heart Association class decreased to 1.1 ± 0.3 and 1.5 ± 0.6 (P = .004). The BA increased to 182° ± 4° in the CC (P < .001) and remained unchanged (137° ± 6°) in the no-CC group. CONCLUSIONS: In selected patients with a BA <145° and coaptation depth ≤10 mm, CC is related to less MR return or persistence, improved EF, and lower New York Heart Association class.

Intermittent tethering of second-order chords after mitral valve repair for bileaflet prolapse.

Mitral valve regurgitation which occurs immediately after repair can be due to anatomic (failure of repair) or functional (systolic anterior motion) reasons. We report a case where a patient with bileaflet prolapse showed, after surgical correction of the disease, moderate to severe regurgitation after cardiopulmonary bypass was stopped. The regurgitation was due to second-order tethering and was successfully treated with second-order chordal cutting.

Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest.

OBJECTIVES: To identify a safety threshold of deep hypothermic circulatory arrest (DHCA) duration; to determine which protection offers the best outcome and whether a 10-min period of cold perfusion (20°C) preceding rewarming can reduce neurological events (NE). METHODS: From January 1988 to April 2009, 456 patients underwent aortic surgery using DHCA: for chronic disease in 239 and acute in 217. Cerebral protection was obtained by straight DHCA (sDHCA) in 69 cases, retrograde perfusion (RCP) in 198 and antegrade perfusion (ACP) in 189. In 247 subjects, a 10-min period of cold perfusion (20°C) preceded rewarming; in 209 rewarming was restarted without this preliminary. RESULTS: Fifty-eight patients (13%) experienced NE. Twenty-two (5%) suffered temporary neurological dysfunction (TND) and 36 (8%) suffered stroke. DHCA duration >30 min was predictive for higher rate of NE (25.2% vs. 2.0%, P 0.001); after this value, only ACP was able to reduce incidence of NE (16.5% vs. 30.5%, P = 0.035). Cold reperfusion before rewarming significantly reduced incidence of NE (7.7% vs. 18.7%, P < 0.001) and extended the safe period to 40 min. Thirty-day mortality was 16.0%. Predictors of higher early mortality were acute aortic disease, longer DHCA, lack of ACP or prompt rewarming when DHCA >30 min and postoperative stroke. CONCLUSIONS: sDHCA remains a safe and easy tool for cerebral protection when DHCA duration is expected to be less than 30 min. When aortic surgery requires a longer period, ACP should be instituted. Before rewarming, a 10-min period of cold perfusion significantly reduces incidence of NE.

Surgical treatment of functional mitral regurgitation.

Incidence of functional mitral regurgitation (FMR) is increasing due to aging and better survival after acute myocardial infarction, the most frequent cause of FMR. At the basis of FMR there is a displacement of one of both papillary muscle(s) and/or annular enlargement, which can be primitive or, more often, secondary. There is general agreement that its natural history is unfavorable, as witnessed by a considerable body of evidences. However, even if there is no clear evidence that surgical treatment of FMR changes consistently the outcome of patients with this disease, at least in terms of survival, there are some studies which show that function improves, as well as the global quality of life. The guidelines reflect this uncertainty, providing no clear indications, even in the gradation of severity of the FMR. Surgical techniques are variable and are mainly addressed to the annulus (restrictive annuloplasty), which is only a part of the anatomic problem related to FMR. Insertion of a prosthesis inside the native valve is appearing more and more a valuable option rather than a bail out procedure. On the other side, techniques addressed to modify the position of the papillary muscles appear to be still under investigation and not yet in the armamentarium of surgical treatment of FMR. Even after many years, rules are not established and results are fluctuating, but how and when to treat FMR is becoming more and more a topic of interest in cardiac surgery.

Management of retained intervention guide-wire: a literature review.

Percutaneous coronary angioplasty is increasingly employed in the treatment of patients with complex coronary artery disease. Different steerable guide wires used to open occluded vessel and facilitate balloon and stent deployment. However, the guide-wire itself is not without hazard: it may perforate or dissect the vessel, but fracture or entrapment is uncommon. Its management depends on the clinical situation of the patient, as well as the position and length of the remnant. In this review we discuss the angioplasty guide-wire fracture and entrapment risk factors, potential risks and management.

Functional tricuspid regurgitation and the right ventricle: What we do not know is more than we know.

The tricuspid valve (TV) lies in between the right atrium and the right ventricle (RV), consisting of annulus, leaflets, chords and papillary muscles. The RV appears triangular-shaped in a lateral view and crescent-shaped in a cross-section one. In normal conditions, the septum is concave toward the left ventricle (LV) in both systole and diastole and the RV volume is larger than the LV volume, although its mass is a third of the LV. The strict relationship between the TV apparatus and the RV underlies the physiological mechanism of TV functioning, and so, the RV plays an important role in case of functional tricuspid regurgitation. Nevertheless, the systematic assessment of RV is still not performed mainly due to lack of standardization. Hence, new echocardiographic guidelines have recently been proposed to standardize the RV assessment using transthoracic 2D­echocardiography. 3D-echocardiography and MRI are more useful to measure volumes and ejection fraction; in particular, MRI is able to provide a tissue evaluation. Today, surgical strategies are directed mainly to the annulus with fluctuating results because functional tricuspid regurgitation is not due only to the annulus but also to the RV, which is difficult to assess, due to its evolution being unpredictable and complicated by the interaction with LV.

Left main approach for retrieval of retained guidewire fragment.

Entrapment and detachment of guidewire fractures during percutaneous coronary intervention (PCI) are very rare, but can lead to life-threatening complications such as embolization, thrombus formation, and perforation. Surgical extraction of the remnant fragments is recommended if the percutaneous retrieval is not possible. We present a case of remnant guidewire into the left anterior descending artery (LAD) and aorta that led to acute coronary thrombosis following primary angioplasty. Surgical retrieval was possible only through a left main (LM) approach.

Monitoring metformin in cardiac patients exposed to contrast media using ultra-high-performance liquid chromatography tandem mass-spectrometry.

BACKGROUND: There is no evidence that the use of contrast media (CM) in diabetic patients with serum creatinine <130 µmole/L leads to metformin accumulation and subsequent lactic acidosis. Therefore, the objective of this investigation was to monitor cardiac patients for the effects of CM on their metformin plasma concentration and serum creatinine clearance (ClCr). METHODS: Metformin plasma concentrations were measured by a new, fully validated specific, precise, and accurate ultra-high-performance liquid chromatography tandem mass-spectrometric assay. The detection was performed using positive electrospray ionization in the multiple reaction monitoring mode. Fifty patients with serum creatinine levels <130 µmole/L were monitored for the effect of CM exposure on metformin concentration and ClCr. Pharmacokinetic parameters were calculated in 8 of these patients, and metformin accumulation was monitored in 10 patients before and after their exposure to CM. RESULTS: Linear response (r ≥ 0.998) was observed over the range of 5-2000 ng/mL of metformin, with the lower limit of quantification of 2.3 ng/mL. The intraday and interday precision (relative standard deviation) values were <13%, and the accuracy (relative error) was <-10% for metformin concentrations. The assay was sensitive to follow the pharmacokinetics of metformin in humans during a dosing interval after an oral dose at steady state. Metformin pharmacokinetic parameters were estimated in 8 patients exposed to CM. The mean C(max) of 1.9 ± 0.6 mg/L was attained at 4.1 ± 1.9 hours. There was no evidence of any drug accumulation or altered elimination due to the exposure to CM in the current population. ClCr showed no significant difference (P > 0.05) before (92.8 ± 11.3 mL/min) and after 48 hours (90.5 ± 10.5 mL/min) of exposure to CM. CONCLUSIONS: Our data suggest that the recommendation to withhold metformin in diabetic patients during CM exposure could be revised to withholding the drug only in patients with moderate to severe renal dysfunction.

Posterior chordal cutting in rheumatic mitral regurgitation due to hypomobility of the posterior leaflet.

A technique is described for correction of mitral regurgitation when the posterior leaflet has a reasonable length (approximately 10 mm), but its movements are limited by thickened and short chords. To avoid further retraction when a band or a ring is positioned to force leaflets coaptation, native chords are replaced by artificial chords (leaving 10 mm of extra length), which are then cut. In 6 patients, after 6 months of follow-up, the results are good.

The clinical significance of cardiac troponins in medical practice.

Troponins are regulatory proteins that form the cornerstone of muscle contraction. The amino acid sequences of cardiac troponins differentiate them from that of skeletal muscles, allowing for the development of monoclonal antibody-based assay of troponin I (TnI) and troponin T (TnT). Along with the patient history, physical examination and electrocardiography, the measurement of highly sensitive and specific cardiac troponin has supplanted the former gold standard biomarker (creatine kinase-MB) to detect myocardial damage and estimate the prognosis of patients with ischemic heart disease. The current guidelines for the diagnosis of non-ST segment elevation myocardial infarction are largely based on an elevated troponin level. The implementation of these new guidelines in clinical practice has led to a substantial increase in the frequency of myocardial infarction diagnosis. Automated assays using cardiac-specific monoclonal antibodies to cardiac TnI and TnT are commercially available. They play a major role in the evaluation of myocardial injury and prediction of cardiovascular outcome in cardiac and non-cardiac causes. In this review we discuss the clinical applications of cardiac troponins and the interpretation of elevated levels in the context of various clinical settings.

Surgical treatment of functional mitral regurgitation in dilated cardiomyopathy.

Functional mitral regurgitation is a significant complication of end-stage cardiomyopathy. Dysfunction of one or more components of the mitral valve apparatus occurs in 39-74% and affects almost all heart failure patients. Survival is decreased in subjects with more than mild mitral regurgitation irrespective of the aetiology of heart failure. The goal of treating functional mitral regurgitation is to slow or reverse ventricular remodelling, improve symptoms and functional class, decrease the frequency of hospitalization for congestive heart failure, slow progression to advanced heart failure (time to transplant) and improve survival. This article reviews the role of mitral valve surgery in patients with heart failure and dilated cardiomyopathy.