Left ventricular outflow tract area after percutaneous transseptal transcatheter mitral valve implantation: A three-dimensional transesophageal echocardiography study

BACKGROUND

Left ventricular (LV) outflow tract (LVOT) obstruction increases mortality in patients undergoing transcatheter mitral valve implantation (TMVI) in degenerated bioprostheses, annuloplasty rings, and native mitral valves. We aimed to evaluate the LVOT area after TMVI using 3-dimensional (3D) transesophageal echocardiography (TEE) and to investigate the preprocedural cardiac geometry that affects the LVOT area after TMVI.

METHODS

We retrospectively reviewed echocardiography data in 43 patients who had TMVI. A change in pressure gradient across LVOT from before to after TMVI (∆PG) and postprocedure 3D LVOT cross-sectional area at the level of the most distal portion of the mitral valve stent that was closest to the LV apex were assessed as evidence of LVOT narrowing.

RESULTS

Transcatheter mitral valve implantation with the use of balloon-expandable valve system was performed for 24 bioprostheses, 7 annuloplasty rings, and 12 native valves. Compared to patients without increase in LVOT gradient (∆PG <10 mm Hg; n = 33), patients with increase in LVOT gradient (∆PG ≥10 mm Hg; n = 10) had smaller LV end-systolic volume (LVESV), greater LV ejection fraction (LVEF), and smaller aorto-mitral (AM) angle. The LVOT area at the valve stent distal edge showed strong association with ∆PG (r = -.68, P < .0001). Only a small AM angle was associated with a small LVOT area at the valve stent distal edge on multivariable analysis, independent of LVESV and LVEF.

CONCLUSION

Small LV size, preserved LVEF, and small AM angle were associated with LVOT narrowing. 3D-derived AM angle might be independently associated with LVOT narrowing in patients undergoing transcatheter mitral valve-in-valve, valve-in-ring, and valve-in-native valve implantation, independent of LVESV and LVEF.

Impact of Percutaneous Edge-to-Edge Repair in Patients With Atrial Functional Mitral Regurgitation

BACKGROUND

The aim of this study was to clarify the clinical outcomes of patients with atrial functional mitral regurgitation (FMR) who underwent the MitraClip procedure compared with those with conventional FMR and sinus rhythm (SR).Methods and Results:Of 303 patients with FMR who underwent the MitraClip procedure, 40 with "atrial-FMR" defined as FMR with permanent atrial fibrillation and normal left ventricular (LV) function/size and 115 with "sinus-FMR" defined as FMR with SR and LV dysfunction were reviewed. Transthoracic and 3D transesophageal echocardiography, and the cardiac complication rate (composite of all-cause death, heart failure admission, mitral valve (MV) surgery, and redo MitraClip procedure) during the 12-month follow-up were compared between the groups. After the MitraClip procedure, reductions in the mitral annular area and its anteroposterior dimension and in the leaflet closure area were observed in both groups. MV orifice area was smaller with greater transmitral pressure gradient (P<0.05) after the procedure in atrial-FMR patients than in those with sinus-FMR. The prevalence of residual MR was similar, but significant tricuspid regurgitation (TR) was more prevalent in the atrial-FMR group at follow-up. Cardiac complication rate was comparable between groups (20% vs. 25%, P=0.63).

CONCLUSIONS

Reduction of MR occurred in atrial-FMR probably because of the increase in leaflet coaptation area. Significant TR was more common after the MitraClip procedure in patients with atrial-FMR than with sinus-FMR. However, mid-term outcomes were comparable between patients with atrial-FMR and sinus-FMR.

An association between right ventricular dysfunction and sudden cardiac death

BACKGROUND

The effectiveness of severely reduced left ventricular ejection fraction (LVEF <35%) as a predictor of sudden cardiac death (SCD) has diminished, and improvements in risk stratification await discovery of novel markers. Right ventricular (RV) abnormalities can be observed in conditions such as chronic obstructive pulmonary disease and sleep apnea, which have been linked to SCD.

OBJECTIVE

The purpose of this study was to evaluate whether RV abnormalities were associated with SCD after accounting for LVEF and other patient characteristics.

METHODS

In a large, prospective ongoing community-based study of SCD in the Portland, Oregon, metropolitan area, SCD cases (age ≥18 years; 2002-2014) were compared to controls with coronary artery disease but no SCD. Using a novel archive of digital echocardiograms, a standardized approach was used to evaluate RV basal diameter, RV end-diastolic area, and right ventricular fractional area change (RVFAC).

RESULTS

A total of 350 subjects were studied, including 81 SCD cases (age 68.7 ± 13.6 years; 73% male) and 269 controls (age 66.5 ± 10.2 years; 69% male). In multivariate analysis, RVFAC was significantly associated with SCD (odds ratio 1.14 for each 5% decrease; 95% confidence interval 1.03-1.25; P = .01). When modeled with LVEF ≤35%, RVFAC ≤35% was significantly associated with increased risk of SCD. Individuals with both left ventricular and RV dysfunction had a 3× higher odds of SCD than those with neither (odds ratio 3.19; 95% confidence interval 1.33-7.68; P = .01).

CONCLUSION

RV dysfunction was associated with a significantly increased risk of SCD independent of LVEF and, when combined with LVEF, had additive effects on SCD risk.

Left atrial pressure is associated with iatrogenic atrial septal defect after mitral valve clip

OBJECTIVES

Mitral valve (MV) clip procedure requires interatrial trans-septal puncture to access the left atrium (LA). Iatrogenic atrial septal defect (iASD) is not uncommon and may remain for a while. However, haemodynamic and echocardiographic determinants of persistent iASD are not well investigated. We sought to find haemodynamic and echocardiographic determinants of iASD after MV clip.

METHODS

A total of 131 patients with grades 3 to 4+ mitral regurgitation who underwent MitraClip and completed invasive haemodynamic measurement, baseline, 1 month and approximately 12 months of transthoracic echocardiography (TTE) follow-up were retrospectively reviewed.

RESULTS

TTE at 1 month showed persistent iASD in 57% (1M-iASD). Mean LA pressure after clip was significantly higher in patients with 1M-iASD than patients without 1M-iASD (17±6 mm Hg vs 15±5 mm Hg, p=0.01). Among patients with 1M-iASD, 24 patients (35%) had persistent iASD at 12 months (12M-iASD). Mean LA pressure after clip was significantly higher in patients with 12M-iASD than patients without 12M-iASD (19±6 mm Hg vs 16±6 mm Hg, p=0.04). Patients with 12M-iASD did not significantly differ from patients without 12M-iASD in terms of right heart enlargement, estimated systolic pulmonary artery pressure, New York Heart Association functional class and brain natriuretic peptide at 12 months. Logistic regression analysis, however, showed that mean LA pressure after clip was significantly associated with persistent iASD at 12 months in patients with 1M-iASD even after adjustment for cardiac index after clip and the prevalence of mitral regurgitation ≥3+ at 12 months (OR 1.10 per 1 mm Hg, 95% CI 1.01 to 1.21, p=0.04).

CONCLUSIONS

Elevated LA pressure after MV clip was associated with persistent iASD.

Relation Between Pulmonary Venous Flow and Left Atrial Pressure During Percutaneous Mitral Valve Repair With the MitraClip

Pulmonary venous (PV) flow may provide valuable information in terms of the severity of mitral regurgitation and left atrial (LA) pressure. We sought to find PV flow determinants of LA pressure during MitraClip procedure. We analyzed 575 PV flows in 290 patients using transesophageal echocardiography before and after MitraClip procedure. We measured peak systolic velocity (Sv), diastolic velocity (Dv), systolic velocity time integral (Svti), diastolic velocity time integral (Dvti), and those systolic to diastolic ratio as PV flow parameters. Systolic PV flow velocity was lower than diastolic PV flow velocity before the procedure, but systolic PV flow velocity markedly increased after the procedure. Peak Sv/Dv ratio and Svti/Dvti ratio after the procedure were significantly higher than those before the procedure (peak Sv/Dv; 1.06 [inter-quartile range (IQR) 0.73 to 1.34] vs 0.32 [IQR 0.03 to 0.55], p <0.001, Svti/Dvti; 1.06 [IQR 0.76 to 1.61] vs 0.26 [IQR 0.02 to 0.51], p <0.001). Peak Sv/Dv ratio and Svti/Dvti ratio were negatively correlated with mean LA pressure and LA pressure V wave, respectively (peak Sv/Dv ratio; r = -0.50 and r = -0.59, Svti/Dvti ratio; r = -0.47 and r = -0.58, p <0.001). In receiver operating characteristics curve assessing the ability of PV flow to predict mean LA pressure ≥20 mm Hg after the successful procedure, the area under the curve of peak Sv/Dv ratio was 0.76 (p <0.001). Peak Sv/Dv ratio <0.98 best predicted LA pressure ≥20 mm Hg with 77% sensitivity and 71% specificity. In conclusion, systolic PV flow velocity immediately increased in response to mitral regurgitation reduction during MitraClip procedure. PV flow velocity, specifically systolic to diastolic ratio, was useful to evaluate invasively determined LA pressure.

Basic fibroblast growth factor stimulates the competence phase of subcultured endothelial cells and the progression phase of primary cultured smooth muscle cells from rat aorta

The proliferative effects of basic fibroblast growth factor (bFGF) on the cell cycle were compared in subcultured endothelial cells (EC) and primary cultured smooth muscle cells (SMC) from rat aorta by monitoring the starting time (an index of the competence phase) and rate (an index of the progression phase) of [3H]thymidine incorporation. Persistent treatment with bFGF (1, 10 and 30 ng/ml) reduced the starting time of EC proliferation in the presence of 1% fetal bovine serum (FBS) in a concentration-dependent manner. The starting time of [3H]thymidine incorporation into EC was reduced by a maximum of 4 h by pretreatment with bFGF for 12 h but not for 3 h. DNA synthesis in EC was inhibited by pretreatment with bFGF for 24 h. The rate of [3H]thymidine incorporation into SMC was accelerated both by persistent treatment with bFGF and pretreatment for 3 h in the presence of 3% FBS. In serum-free medium, bFGF (30 ng/ml) stimulated [3H]thymidine incorporation into SMC but not into EC after incubation for 36 h. Together, bFGF (10 ng/ml) and insulin (10 micrograms/ml) synergistically stimulated [3H]thymidine incorporation into EC, but insulin alone did not. These findings indicate that bFGF is a competence factor in EC and a progression factor in SMC from rat aorta.

Interferon-gamma-activated macrophages enhance angiogenesis from endothelial cells of rat aorta

The influence of interferon-gamma (IFN-gamma), an activator of macrophages, was investigated on angiogenesis in vitro from rat aortic endothelial cells (EC). Subcultured EC were cultured in 0.15% type I collagen gel with 2% fetal bovine serum (FBS)-Dulbecco's modified Eagle's medium. Tube formation by EC began on the first day of culture and reached a plateau that lasted from the second to the eighth day. A peritoneal macrophage preparation was co-cultured on overlaying collagen gel containing EC. The macrophage preparation increased tube length from the second to the fourth day in a time-dependent manner. IFN-gamma (2.2 and 6.5 ng/ml) enhanced the effect of co-cultured macrophages from the fourth to the eighth day. The conditioned media derived from macrophages after 4 and 6 days of exposure to IFN-gamma (6.5 ng/ml) also showed significantly enhanced tube formation induced by macrophage-conditioned medium. However, IFN-gamma (6.5 ng/ml) did not influence the activity of the macrophage-conditioned medium. These results suggest that IFN-gamma enhances angiogenesis from EC of rat aorta by releasing an angiogenic factor from macrophages.

Heparin inhibits the progression phase of subcultured endothelial cell proliferation in rat aorta

The anti-proliferative effects of heparin on subcultured endothelial cells (EC) of rat aorta were investigated to determine whether heparin inhibits the competence phase or the progression phase in the cell cycle using the starting time and the rate of proliferation. Fetal bovine serum (FBS)-stimulated EC proliferation increased to 1.5-times in cell number, but decreased to 0.5-times in 3H-thymidine incorporation, compared with the proliferation of rat primary cultured smooth muscle cells (SMC). The FBS-effects on EC proliferation were attributed to the progression phase rather than the competence phase. Heparin (1, 10 or 100 micrograms/ml) significantly inhibited the proliferation of FBS (5%)-stimulated EC, and the extent of inhibition was the same in both cell number and 3H-thymidine incorporation. In the 3H-thymidine incorporation every 3 hr, heparin reduced the rate of incorporation into G0-arrested EC, but did not affect the starting time of DNA synthesis. When the index of competence phase, starting time, was plotted against that of progression phase, rate of proliferation, the inhibition of heparin was attributed to the progression phase. These results demonstrate that heparin selectively inhibits the progression phase in subcultured EC of rat aorta.

Inhibitory effects of magnoshinin and magnosalin, compounds from "Shin-i" (Flos magnoliae), on the competence and progression phases in proliferation of subcultured rat aortic endothelial cells

Anti-proliferative effects of magnoshinin and magnosalin derived from "Shin-i" (Flos magnoliae) were investigated using subcultured endothelial cells (EC) of rat aorta. The inhibitory effects of magnoshinin were 2-fold greater at 10 micrograms/ml than that of magnosalin on the increase in cell number when EC were stimulated by 5% fetal bovine serum. In the 3H-thymidine incorporation monitored at 3 hr-intervals, magnoshinin (0.1-3 micrograms/ml) prolonged the starting time of DNA synthesis and reduced the rate of incorporation into EC. Magnosalin (0.3-3 micrograms/ml) reduced only the incorporation rate. These results suggest that magnoshinin inhibits both the competence phase and progression phase, but magnosalin preferentially inhibits the progression phase in EC proliferation.

[A female infant of mitochondrial myopathy with findings of active necrosis and regeneration of muscle fibers]

An 8 year-old female infant with the clinical and pathological characteristics of both progressive muscular dystrophy and mitochondrial myopathy was described. Her maternal cousin had clinical and pathological findings of Duchenne muscular dystrophy (DMD). Since the patient had markedly elevated serum CK and calf muscle hypertrophy, her muscle was biopsied and she was diagnosed as having female DMD at the age of 5 years. She had generalized tonic-clonic convulsions and alternate hemiconvulsions for recent 4 years which brought her our hospital. On admission, she had mild generalized muscle atrophy and weakness predominantly in the proximal limbs. The lactate and pyruvate levels in both serum and cerebrospinal fluid were elevated, but with no metabolic acidosis. Serum CK was elevated to 4464 IU/L. Brain CT and MRI showed the expanding arachnoid cyst in the left middle fossa of cranium. In the biopsied left biceps crachii muscle, in addition to numerous ragged-red fibers, there were active muscular fiber necrosis and regeneration and interstitial fibrosis similar to those seen in progressive muscular dystrophy. Biochemically, no decrease or defect in the respiratory chain enzymes was detected. On electron microscopy, a large number of fibers contained aggregates of giant mitochondria with proliferated complicated cristae. Scattered throughout were necrotic muscle fibers filled with phagocytes and regenerating fibers. This patient had the diagnostic features of mitochondrial encephalomyopathy and progressive muscular dystrophy. We supposed that the patient provided very interesting evidences to study the relationship between mitochondrial myopathy and progressive muscular dystrophy.

Intravenous flunitrazepam for status epilepticus

Flunitrazepam (FZP) was administered intravenously, with success, to two patients with status epilepticus. Case 1 was a patient with a tonic-clonic status epilepticus. Intravenous phenytoin had no effect. Case 2 had minor status epilepticus. With the intravenous administration of FZP, diluted 1:10 with distilled water at a dose of 0.03 mg/kg at a slow rate, both patients were relieved of the status epilepticus. Unlike diazepam, FZP neither looks cloudy when diluted with distilled water nor causes angialgia. No disturbances in circulation or respiration occurred. Considering that FZP has a strong anticonvulsant action on status epilepticus, it can be expected to be a useful therapeutic agent for status epilepticus in infants and children.

[A case of MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) with progressive cytochrome c oxidase deficiency]

We report a 9 year-old boy with MELAS. High dosed oral thiamine administration and high fat diet induced remarkable neurological and biochemical improvement. His mother had episodic headaches and hemiplegia, probably MELAS. He complained muscle weakness and repeated episodes of vomiting started from 2 years of age. High levels of serum lactate and pyruvate were recognized, but with no metabolic acidosis. He developed generalized muscle weakness, growth retardation, generalized convulsions and stroke-like episodes at 5 years old. Optic nerve atrophy and mental retardation gradually appeared. A muscle biopsy at 5 years old revealed numerous ragged-red fibers with excess accumulation of lipid droplets and glycogen particles. Scattered fibers had no cytochrome c oxidase (CCO) activity representing focal CCO deficiency. An electron microscopy showed markedly increased number of giant mitochondria filled with markedly proliferated complicated cristae. Pyruvate dehydrogenase complex level in the fibroblasts was within normal ranges. Serum carnitine level was normal. With oral administration of thiamine hydrochloride (1000 mg) and high fat diet (60-70%), muscle weakness improved, and lactate and pyruvate levels in the serum reduced to normal ranges, whereas the mental deterioration, muscle atrophy, pes cavus progressed very slowly. He died from cardiac and renal failures at 9 years old. Autopsied muscles showed a marked decrease in cytochrome c oxidase activity (biochemically 12.8% of the normal level), and almost all muscle fibers had no cytochrome c oxidase activity histochemically. The progression of the MELAS was probably in parallel with the decrease in CCO activity.