Identification of transmembrane protein 168 mutation in familial Brugada syndrome.

Brugada syndrome (BrS) is an inherited channelopathy responsible for almost 20% of sudden cardiac deaths in patients with nonstructural cardiac diseases. Approximately 70% of BrS patients, the causative gene mutation(s) remains unknown. In this study, we used whole exome sequencing to investigate candidate mutations in a family clinically diagnosed with BrS. A heterozygous 1616G>A substitution (R539Q mutation) was identified in the transmembrane protein 168 (TMEM168) gene of symptomatic individuals. Similar to endogenous TMEM168, both TMEM168 wild-type (WT) and mutant proteins that were ectopically induced in HL-1 cells showed nuclear membrane localization. A significant decrease in Na+ current and Nav 1.5 protein expression was observed in HL-1 cardiomyocytes expressing mutant TMEM168. Ventricular tachyarrhythmias and conduction disorders were induced in the heterozygous Tmem168 1616G>A knock-in mice by pharmacological stimulation, but not in WT mice. Na+ current was reduced in ventricular cardiomyocytes isolated from the Tmem168 knock-in heart, and Nav 1.5 expression was also impaired. This impairment was dependent on increased Nedd4-2 binding to Nav 1.5 and subsequent ubiquitination. Collectively, our results show an association between the TMEM168 1616G>A mutation and arrhythmogenesis in a family with BrS.

Prognostic implications of post-discharge hemodynamic congestion assessed by peripheral venous pressure among patients discharged from acute heart failure.

BACKGROUND: Congestion is a major cause of hospitalization for heart failure (HF). Peripheral venous pressure (PVP) strongly correlates with right atrial pressure. We recently reported that high PVP at discharge portends a poor prognosis in patients hospitalized for HF. In the same population, we aimed to analyze changes in PVP after discharge and to evaluate prognostic implications of post-discharge PVP. METHODS: PVP was measured at the forearm vein of 163 patients in the 1-month post-discharge follow-up visit. The primary outcome was a composite of cardiovascular death or re-hospitalization for HF after the 1-month follow-up visit up to 1 year after discharge. RESULTS: Post-discharge PVP correlated with jugular venous pressure, the inferior vena cava diameter, and brain-type natriuretic peptide levels. The cumulative incidence of the primary outcome event was significantly higher in patients with PVP above the median (6 mmHg) than in those with median PVP or lower (39.8% versus 16.9%, Log-rank P = 0.04). Age- and sex-adjusted risk of PVP per 1 mmHg for the primary outcome measure was significant (hazard ratio: 1.12 [95% confidence interval 1.03-1.21]). 35% of patients who had PVP ≤6 mmHg at discharge had PVP >6 mmHg at the 1-month follow-up. PVP significantly decreased from discharge to 1-month follow-up in patients without the primary outcome event (from 6 [4-10] to 6 [4-8] mmHg, P=0.01), but remained high in those with the primary outcome event (from 8 [5-11] to 7 [5-10.5] mmHg, P = 0.9). CONCLUSIONS: PVP measurements during the early post-discharge period may be useful to identify high risk patients. TRIAL REGISTRATION NUMBER: UMIN000034279.

Angiographic evaluation of radial artery injury after transradial approach for percutaneous coronary intervention.

The transradial approach for percutaneous coronary intervention (TRA-PCI) has been increasingly gaining popularity in clinical practice. However, its association with risk for long-term radial artery injury has not been yet thoroughly defined. We retrospectively examined the patients undergoing radial artery angiography (RAG) after TRA-PCI to determine the incidence and risk factors of radial artery injury. The study included 558 patients undergoing follow-up radial artery angiography at 12 month after TRA-PCI. Radial artery injury occurred in 140 patients (25%) with 3 distinct morphological patterns: focal radial artery stenosis (RAS) P.7,7: in 7 patients (1%), diffuse radial artery stenosis (RAS) in 78 patients (14%), and radial artery occlusion (RAO) in 55 patients (10%). Patients with RAS/RAO were more likely to be female, had smaller height and body weight, smaller body mass index and smaller body surface area (BSA) as compared with those without RAS/RAO. Multivariable logistic regression analysis identified BSA (odds ratio, 1.34 per 0.1 m2 increase; 95% confidence interval, 1.07-1.71; p = 0.01) and a history of TRA-PCI (odds ratio, 2.35; 95% confidence interval, 1.16-5.08; p = 0.017) as independent predisposing factors of radial artery injury. In a sub-analysis of 323 patients undergoing both pre-PCI RAG and follow-up RAG, pre-PCI radial diameter as well as BSA and a history of TRA-PCI were independently associated with radial artery injury. Long-term injury after TRA-PCI is considerably common and care should be paid for RAS/RAO, especially for those patients with lower BSA, history of TRA-PCI and small radial artery diameter.

Circulating markers of collagen types I, III, and IV in patients with dilated cardiomyopathy: relationships with myocardial collagen expression.

AIMS: Collagen-derived peptides such as collagen I C-terminal telopeptide (CITP) and procollagen III N-terminal propeptide (PIIINP) have been conventionally used as markers of cardiac fibrosis. Collagen IV 7S domain (P4NP 7S) has been recently reported to be correlated with haemodynamics in patients with acute heart failure. We investigated whether these markers reflect cardiac remodelling and myocardial collagen expression. METHODS AND RESULTS: In 80 patients with dilated cardiomyopathy, relationships of CITP, PIIINP, and P4NP 7S to clinical and echocardiographic variables were analysed. CITP and PIIINP were inversely correlated with estimated glomerular filtration rate (r = -0.41, P < 0.001 and r = -0.32, P = 0.004, respectively); P4NP 7S was positively correlated with B-type natriuretic peptide (r = 0.32, P = 0.003) and γ-glutamyltransferase (r = 0.38, P < 0.001). These correlations were significant even after adjustment by potential confounders, whereas all three collagen markers were not independently correlated with ejection fraction nor with left ventricular (LV) diastolic diameter. In 33 patients undergoing endomyocardial biopsy, myocardial collagen I and III mRNA expressions were correlated with LV end-diastolic volume index (r = 0.42, P = 0.02 and r = 0.54, P = 0.002, respectively), whereas myocardial collagen IV mRNA expression was not correlated with LV end-diastolic volume index nor with ejection fraction. Each collagen-derived peptide was not significantly correlated with the myocardial expression of their corresponding collagen mRNA. CONCLUSIONS: Our study shows that CITP, PIIINP, and P4NP 7S do not reflect myocardial collagen mRNA expression but presumably reflect extra-cardiac organ injury in heart failure.

Liver fibrogenesis marker, 7S domain of collagen type IV in patients with acutely decompensated heart failure: Correlates, prognostic value and time course.

BACKGROUND: Congestion in heart failure (HF) induces multiple organ injury, which may cause remodeling of extracellular matrix. We hypothesized that liver fibrogenesis marker, 7S domain of collagen type IV (P4NP 7S) was correlated with congestion and liver injury in HF. METHODS AND RESULTS: We measured serum P4NP 7S in two cohorts. Cohort 1 included 70 patients undergoing catheterization. P4NP 7S was correlated with pulmonary capillary wedge pressure, right ventricular and atrial pressure (r=0.50, P<0.001, r=0.42, P<0.001, r=0.39, P=0.001, respectively) but not with cardiac index (r=-0.05. P=0.7). Cohort 2 included 145 patients with acute HF, in whom we serially measured P4NP 7S at admission, discharge, early (1-month) and late (6-month) post-discharge period. γ-Glutamyltransferase and B-type natriuretic peptide were independently correlated with P4NP 7S at discharge. The cumulative 1-year incidence of death or HF hospitalization was much higher in the 3rd tertile of P4NP 7S than in the 1st and 2nd tertiles (50%, 25%, and 24%, Log-rank P=0.004). P4NP 7S enhanced risk classification when added to conventional risk factors (net reclassification improvement=0.47, P=0.02). In patients without early readmission, P4NP 7S decreased during hospitalization and remained low for up to 6months, whereas in patients with early readmission, P4NP 7S was persistently elevated during hospitalization, further increased at second admission, and remained high at 6months. CONCLUSION: P4NP 7S was correlated with hemodynamics. The results shed new light on the pathophysiology of HF.

Diagnosis of coronary vasospasm by detection of postischemic regional left ventricular delayed relaxation using echocardiographic evaluation with color kinesis.

BACKGROUND: Coronary vasospasm has been diagnosed by invasive provocative procedures during coronary arteriography. It would be useful to have a reliable, noninvasive, and safe diagnostic method for coronary vasospasm. Regional left ventricular (LV) diastolic dysfunction may persist without systolic dysfunction after an episode of coronary vasospasm. Color kinesis (CK) has been recently developed to facilitate the echocardiographic evaluation of regional wall motion. HYPOTHESIS: Color kinesis may be useful for diagnosis of coronary vasospasm by detection of postischemic regional LV diastolic wall motion abnormality. METHODS: Fifty-one consecutive patients with the last chest symptom within 2 weeks (4 +/- 3 days) were studied echocardiographically. Regional fractional area change during the first 30% of LV filling time in percentage of the segmental end-diastolic area change (CK diastolic index) was used to identify diastolic endocardial motion asynchrony. RESULTS: After diagnostic coronary arteriography with spasm provocation, 26 patients were diagnosed with coronary spastic angina (CSA) and the other 25 with chest pain syndrome (CPS). Regional delayed relaxation (CK-diastolic index < or = 50%) or diastolic asynchrony had been observed in at least one region in 25 (96%) patients with CSA, whereas it had been noted in 2 (8%) patients with CPS. In 17 (65%) patients with CSA, it had been detected in multiple vascular territories, suggesting multivessel spasm. The diastolic asynchrony disappeared in CSA after a month of angina-free period. CONCLUSION: Analysis of CK images allows identification of regional LV delayed relaxation or diastolic asynchrony in patients with coronary vasospasm, differentiating them from patients with chest pain syndrome (sensitivity 96%, specificity 92%).

High remnant lipoprotein levels in patients with variant angina.

BACKGROUND: Dyslipidemia with increased oxidative stress but without elevation of low-density lipoprotein cholesterol has been recently implicated in the pathogenesis of coronary vasospasm. HYPOTHESIS: Disordered triglyceride-rich lipoprotein metabolism may be linked to the genesis of coronary artery spasm. METHODS: Both serum remnant lipoprotein (RLP) and alpha-tocopherol levels were determined in 18 patients with the active stage of variant angina (VA), in 16 patients with the inactive stage of variant angina (IVA), and in 19 control subjects (CONTROL). RESULTS: The RLP levels were significantly (p < 0.05) higher in VA (6.4 +/- 2.7 mg/dl) than in IVA (4.4 +/- 1.5 mg/dl). In contrast, alpha-tocopherol levels were significantly lower in VA than that in CONTROL. Serum trigyceride levels were not significantly different among the study groups, although serum high-density lipoprotein cholesterol levels were significantly lower in VA than in CONTROL. Smoking was significantly (p < 0.05) more prevalent in VA (72%) than in IVA (25%) and CONTROL (37%). Serum RLP levels correlated positively with triglyceride levels (R = 0.73) and correlated inversely with alpha-tocopherol levels (R = -0.31) significantly in all study subjects. CONCLUSIONS: Patients with active stage of variant angina had higher RLP levels than inactive patients with variant angina and lower alpha-tocopherol levels than control subjects. Disordered triglyceride-rich lipoprotein metabolism with increased oxidative stress appears to be linked to the activity of coronary vasospasm, suggesting a possible role in its pathogenesis.

Increased oxidative stress with elevated serum thioredoxin level in patients with coronary spastic angina.

BACKGROUND: Increased oxidative stress has been implicated in the pathogenesis of coronary vasospasm. Thioredoxin (TRX) is a redox-active protein that is known to be induced by oxidative stress. HYPOTHESIS: The serum TRX level may be high in patients with coronary vasospasm. METHODS: The serum TRX level was determined using an enzyme-linked immunosorbent assay in 21 patients with the active stage of coronary spastic angina (CSA), in 18 patients with the inactive stage of CSA (iCSA), in 24 control subjects without coronary artery disease (Control), and in 20 patients with stable effort angina (SEA). RESULTS: Serum TRX levels (mean +/- standard deviation ng/ml) were significantly higher in CSA (64 +/- 44) than in iCSA (28 +/- 26), in Control (34 +/- 15), and in SEA (36 +/- 16). In contrast, serum alpha-tocopherol levels (mg/g lipids) were significantly lower in CSA (2.8 +/- 0.7) than in Control (4.0 +/- 1.2) and in SEA (3.2 +/- 0.4). Current smoking was significantly more prevalent in CSA (76%) than in any of the other groups. No significant correlation was found between the serum level of TRX and alpha-tocopherol in the study subjects. In nine patients with CSA, the serum TRX level decreased (93 +/- 41 --> 41 +/- 35 ng/ml) and the alpha-tocopherol level increased (2.7 +/- 0.6 --> 3.2 +/- 0.7 mg/g lipids) significantly under medication with calcium entry blockers after an at least 3-month angina-free period. CONCLUSIONS: Patients with coronary spastic angina had a higher serum TRX level associated with a lower serum level of antioxidant vitamin E, with redox equilibrium appearing to be related to the disease activity of coronary vasospasm in these patients. Oxidative stress may be related to the genesis of coronary vasospasm.

Myocardial expression level of neural cell adhesion molecule correlates with reduced left ventricular function in human cardiomyopathy.

BACKGROUND: Recently, we screened for cardiac genes induced by metabolic stress and identified neural cell adhesion molecule (NCAM) as a candidate. This study aimed to clarify the expression pattern of NCAM in human cardiomyopathy. METHODS AND RESULTS: A total of 64 cardiac tissue samples of patients with dilated cardiomyopathy were dichotomized according to the immunohistochemically determined signal intensity of NCAM staining (NCAM-high and NCAM-low groups). Clinical and hemodynamic data of the patients were compared between the 2 groups. Fibrosis area, left ventricular end-diastolic volume index, and left ventricular diastolic pressure were greater in the NCAM-high group (22.8% versus 11.6%, P<0.05; 130.3±57.6 versus 104.8±31.7 mL/m(2), P<0.05; 14.3±8.0 versus 8.8±4.7 mm Hg, P<0.005; respectively). Incidence of cardiac death and admission for worsening heart failure was higher in the NCAM-high group during a follow-up of 6.3 years (log-rank P<0.05). Another 18 tissue samples were analyzed to determine the relationships between expression level of NCAM and major metabolic genes as well as hemodynamic parameters. The mRNA level of NCAM correlated with the serum (r=0.58; P=0.01) and mRNA levels (r=0.61; P=0.008) of brain-derived natriuretic peptides. It was also correlated with the mRNA levels of proliferator-activated receptor-γ coactivator-1 α (r=0.69; P=0.002) and the nuclear respiratory factor 1 (r=0.74; P<0.001). CONCLUSIONS: Expression of NCAM was associated with worsening hemodynamic parameters and major metabolic genes. Together with our previous findings, these data support the involvement of NCAM in left ventricular remodeling, revealing new insights into the pathophysiology of heart failure.

Effects of postischemic regional left ventricular diastolic wall motion abnormalities or delayed relaxation following coronary vasospasm on global diastolic function.

BACKGROUND: Regional left ventricular (LV) diastolic wall motion abnormalities detected by color kinesis (CK), an echocardiographic technique, may be a more sensitive measure to postischemic damage following coronary spasm than parameters of global diastolic function. METHODS AND RESULTS: Regional LV diastolic wall motion was evaluated by using CK in 18 patients with variant angina on the day following coronary spasm, which was induced by intracoronary acetylcholine. Fractional regional LV cavity area expansion in the short-axis view during the first 30% of the LV filling time, was used to identify postischemic asynchronous diastolic wall motion. Regional delayed relaxation was observed in any of the LV regions in all the patients, who were divided into 2 groups (Group S: 7 patients with single-vessel spasm with regional delayed relaxation in one area. Group M: 11 patients with multivessel spasm or spasm of the proximal left anterior descending branch with regional delayed relaxation in multiple areas). In Group S, no abnormality (0%) was noted in any of the indexes of global diastolic function including the isovolumic relaxation time, the ratio of peak rapid filling to peak atrial filling velocities and the deceleration time. In contrast, in 5 (45%) of the Group M patients, abnormalities were noted in all of those indexes. CONCLUSIONS: Postischemic regional LV-delayed relaxation following coronary vasospasm was detected sensitively by analysis of CK images. The indexes of global LV diastolic function are insensitive to postischemic damage following single vessel spasm, although they are somewhat sensitive following multivessel spasm.

Serum thioredoxin and alpha-tocopherol concentrations in patients with major risk factors.

BACKGROUND: Oxidative stress, which is thought to be increased in subjects with various coronary risk factors, induces thioredoxin (TRX), a redox-active protein. METHODS AND RESULTS: To determine whether oxidative stress is increased, serum concentrations of both TRX and alpha-tocopherol (vitamin E) were determined in 12 control subjects without any coronary risk factors (CONTROL), 6 current smokers (SMOKING), 19 hypertensive patients (HT), 7 hypercholesterolemic patients (HC) and 14 subjects with multiple risk factors (MULTIPLE). Patients with diabetes mellitus were not included. The serum TRX concentrations (mean +/- SD ng/ml) were significantly higher in SMOKING (41+/-10), HT (41+/-17), HC (48+/-15) and MULTIPLE (46+/-15) than in CONTROL (24+/-11). The serum alpha-tocopherol concentrations (mg/g lipids) were not significantly different among CONTROL (4.0+/-0.7), SMOKING (4.0+/-0.8), HT (4.1+/-0.6) and HC (4.2+/-0.6), although the concentration was significantly lower in MULTIPLE (3.3+/-0.7) than in any of the other study groups. CONCLUSIONS: SMOKING, HT, HC and MULTIPLE had significantly higher serum TRX concentrations than CONTROL, suggesting increased oxidative stress. MULTIPLE had a lower serum concentration of antioxidant alpha-tocopherol than any of the other study groups, suggesting impaired or exhausted defense against chronic oxidative stress in the presence of the multiple risk factors.

Diagnosis of multivessel coronary vasospasm by detecting postischemic regional left ventricular delayed relaxation on echocardiography using color kinesis.

BACKGROUND: It is not known whether multivessel coronary spasm occurs spontaneously in patients who have variant angina (VA) with demonstrated multivessel spasm induced by intracoronary injection of acetylcholine (ACh). Regional left ventricular (LV) diastolic dysfunction or wall motion abnormality may persist after an episode of coronary vasospasm. Color kinesis (CK) is a recent development that facilitates the echocardiographic evaluation of regional diastolic wall motion. METHODS AND RESULTS: Regional diastolic wall motion was evaluated using CK in 26 patients with VA within 1 week of the last episode of angina. The LV segmental filling fraction in the short-axis view during the first 30% of the diastolic filling time, expressed as a percentage, was used to objectively identify postischemic diastolic endocardial motion asynchrony. Diastolic asynchrony or regional LV delayed relaxation was noted in all 26 (100%) patients and in 14 (54%) it was detected in multiple vascular territories, suggesting multivessel spasm. Multivessel spasm was induced by ACh in 11 (79%) of the patients with suspected multivessel spasm by CK. In 11 (92%) of the 12 patients with multivessel spasm induced by ACh multiple regions of delayed relaxation had been noted by CK. The regions of delayed relaxation were largely consistent with the territories perfused by the arteries reacting to ACh (sensitivity: 96%, specificity: 91%). CONCLUSION: ACh induced spasm in the same coronary arteries as those perfusing the regions with delayed diastolic wall motion detected by CK in most of the patients with VA, suggesting that multivessel spasm does occur spontaneously in patients with susceptible arteries.