Shigeshi Kamikawa

Coronary pressure measurement to determine treatment strategy for equivocal left main coronary artery lesions

It is often hard to select a treatment strategy for equivocal left main coronary artery (LMCA) disease. We investigated the usefulness of coronary pressure (CP) measurement for determining the treatment strategy in intermediate LMCA disease. We measured CP in 15 consecutive patients with equivocal LMCA disease (age 67.6 ± 7.5 years, 14 males). Myocardial fractional flow reserve (FFRmyo) was obtained as the ratio of CP distal to the lesion/aortic pressure under maximal coronary dilation. Patients with FFRmyo ≥0.75 and <0.75 received medical therapy and coronary artery bypass grafting (CABG), respectively, and were followed up for 32.5 ± 9.7 (20–47) months. Eight patients received medical therapy and 7 patients underwent CABG in accordance with the FFRmyo criteria noted above. FFRmyo of the LMCA was 0.91 ± 0.01 and 0.61 ± 0.03 in patients who received medical and surgical therapy, respectively. Neither reference vessel diameter, minimal lumen diameter, nor percent diameter stenosis was significantly different between patients who received medical and surgical therapy. During the follow-up period, no patients with medical therapy showed symptoms due to the LMCA lesion. Similarly, 5 of 7 patients with CABG showed improvement of symptoms and the remaining 2 patients were hospitalized with congestive heart failure. No cardiac death was recorded in the patients with medical or surgical therapy. In conclusion, the present results clearly demonstrated that CP is clinically useful for determining the treatment strategy for equivocal LMCA lesions but coronary angiography is not.

Combination therapy of calcium channel blocker and angiotensin II receptor blocker reduces augmentation index in hypertensive patients.

Introduction:The optimal combination treatment for hypertension has not been established. We investigated the effect of a calcium channel blocker or a diuretic added to angiotensin II receptor blockers (ARBs) on the augmentation index (AI), as a marker of arterial stiffness and wave reflection, in hypertensive patients. Methods:Thirty-seven patients treated with ARBs were randomly allocated to either of the 2 groups receiving an ARB plus azelnidipine (AZ group) or trichlormethiazide (TCM group). Changes in brachial blood pressure (BP), AI, high-sensitive C-reactive protein (hsCRP), and serum asymmetric dimethylarginine, as an endogenous nitric oxide synthase inhibitor, were determined. Results:Systolic and diastolic blood pressure after 6 months were significantly reduced in both the groups similarly; however, after adjustment for baseline covariates, the extent of the reduction in AI (%) in the AZ group was significantly greater than in the TCM group (between-group difference was 3.2; 95%CI: 0.2–6.3; P = 0.03). The reduction of high-sensitive C-reactive protein (mg/L) and serum asymmetric dimethylarginine (&mgr;mol/L) was significantly greater in the AZ group than in the TCM group (between-group difference was 0.18 and 0.05; 95%CI: −0.01 to 0.36 and −0.01 to 0.11; P = 0.04 and 0.02, respectively). Further, when patients were analyzed according to age younger than 60 years or older than 60 years, the reduction in AI in the AZ group aged older than 60 years was significantly greater than in the TCM group. Conclusion:The results suggest that azelnidipine has a more beneficial effect on vascular properties in combination therapy with ARB than trichlormethiazide.

Augmentation index is associated with B-type natriuretic peptide in patients with paroxysmal atrial fibrillation

B-type natriuretic peptide (BNP) levels have been shown to be elevated in patients with paroxysmal atrial fibrillation (PAF); however, the underlying mechanisms have not been fully elucidated. Earlier, we reported that an increase in the augmentation index (AI), which is an index of wave reflection and arterial stiffness, is associated with PAF. In this study, we investigate the relationship between the BNP level and AI in patients with PAF. We enrolled 92 patients with a history of PAF and 90 age- and gender-matched individuals without PAF. AI was calculated using applanation tonometry of the radial artery when all patients were on sinus rhythm. Plasma BNP levels were measured simultaneously. An arterial stiffness parameter, the cardio-ankle vascular index (CAVI), was also evaluated. The increased AI in patients with PAF correlated with the elevation of the BNP level (r=0.47, P<0.01). When PAF patients were classified into tertiles on the basis of the BNP level, the left atrial volume index, left ventricular mass index, AI and CAVI increased, and mitral annular e′ velocity (e′), as an index of left ventricular diastolic pressure, decreased with BNP tertiles. AI was also associated with e′ and left ventricular mass index. Multiple regression analysis showed that the AI in PAF patients independently correlated with BNP levels. This study showed that AI was an independent correlate of the BNP level in PAF patients. Left ventricular diastolic dysfunction, which linked to an increase in arterial stiffness, may be involved in the elevated BNP level.

Coronary pressure measurement to identify the lesion requiring percutaneous coronary intervention in equivocal tandem lesions.

ObjectivesNo reliable methods are available for determining application of percutaneous coronary intervention for treatment of equivocal tandem lesions. We investigated whether coronary pressure measurement is useful for determining the lesion that requires percutaneous coronary intervention in tandem lesions. MethodsWe measured coronary pressure in 72 consecutive patients with tandem lesions. Myocardial fractional flow reserve (FFRmyo) was obtained as the ratio of coronary pressure distal to the lesion/aortic pressure under maximal hyperemia. If the FFRmyo across the tandem lesions was ≥0.75, we deferred percutaneous coronary intervention for the lesion. When the tandem lesions showed FFRmyo<0.75, percutaneous coronary intervention was performed on the lesion that showed angiographically higher stenosis. When FFRmyo was <0.75 after one-lesion percutaneous coronary intervention, this intervention was carried out on the remaining lesion. ResultsWe deferred percutaneous coronary intervention for 26 patients (36.1%), and performed percutaneous coronary intervention in 46 patients (63.8%). We performed percutaneous coronary intervention for one lesion in 19 patients (26.4%) and for both lesions in 27 patients (37.5%). Among patients in whom percutaneous coronary intervention was deferred, only two patients (7.7%) required target lesion revascularization during the follow-up period. This rate was not higher than that in the 46 patients who underwent percutaneous coronary intervention for one or two lesions (six patients, 13.0%). Similarly, the target lesion revascularization in lesions with initially deferred percutaneous coronary intervention (5.6%, 4/71 lesions) was not higher than that in lesions with percutaneous coronary intervention (15.1%, 11/73 lesions). Major cardiac events, cardiac death and acute myocardial infarction, did not occur in patients with deferred percutaneous coronary intervention and in those with percutaneous coronary intervention during the follow-up period. ConclusionOur results clearly showed that coronary pressure measurement was clinically useful for identifying equivocal tandem lesions requiring percutaneous coronary intervention.

Increased Augmentation Index of the Radial Pressure Waveform in Patients with Paroxysmal Atrial Fibrillation

Objective: The augmentation index, a marker of wave reflection, has been reported to reflect vascular properties and to determine left ventricular (LV) characteristics. We investigated the relationship between the augmentation index and paroxysmal atrial fibrillation (AF). Methods: A total of 244 outpatients (122 patients with paroxysmal AF and 122 age-, and gender-matched controls without paroxysmal AF) were examined during sinus rhythm. The augmentation index was calculated from the radial arterial waveform using applanation tonometry methods. Results: After adjusting for age, gender, heart rate, and medications, the augmentation index was significantly higher in patients with paroxysmal AF than in subjects without paroxysmal AF (means ± SE: 88.9 ± 1.0 and 81.8 ± 1.0%, respectively; p < 0.001). In all subjects, an increase in the augmentation index was significantly correlated with LV hypertrophy and left atrial enlargement. Multiple logistic analysis revealed that an increase in the augmentation index was significantly related with paroxysmal AF, and the adjusted odds ratio of paroxysmal AF was approximately 1.8 for each 10% augmentation index increase (p < 0.01). Conclusion: An increase in the augmentation index was independently associated with paroxysmal AF. This result suggests that enhanced wave reflection may be related to the development of AF.

AHR, a novel acute hypoxia‐response sequence, drives reporter gene expression under hypoxia in vitro and in vivo

ADAMTS1 (a disintegrin and metalloproteinase with thrombospondin motifs 1) is an early immediate gene. We have previously reported that ADAMTS1 was strongly induced by hypoxia. In this study, we investigated whether ADAMTS1 promoter‐driven reporter signal is detectable by acute hypoxia. We constructed the GFP (green fluorescent protein) expression vector [AHR (acute hypoxia‐response sequence)‐GFP] under the control of ADAMTS1 promoter and compared it with the constitutive GFP‐expressing vector under the control of CMV (cytomegalovirus promoter‐GFP). We transduced AHR‐GFP and examined whether GFP signals can be detected under the acute hypoxia. When the human umbilical vein [HUVEC (human umbilical vein endothelial cells)] was transduced under normoxia, there were few GFP signals, while CMV‐GFP showed considerable GFP signals. When HUVEC was stimulated with hypoxia, GFP signals from AHR‐GFP gene were induced under hypoxic conditions. Notably, the GFP signals peaked at 3 h under hypoxia. In ischaemic hind limb model, transduced AHR‐GFP showed hypoxic induction of GFP signals. In summary, we have demonstrated that the AHR system induced the reporter gene expression by acute hypoxia, and its induction is transient. This is the first report showing the unique acute hypoxia‐activated gene expression system.

Arterial stiffness determined according to the cardio-ankle vascular index is associated with paroxysmal atrial fibrillation: a cross-sectional study

Background Several lines of evidence suggest that atrial fibrillation (AF) may be a consequence of vascular disease. We investigated the relationship between cardio-ankle vascular index (CAVI), a new index of arterial stiffness, and the presence of paroxysmal AF (PAF). Methods and results 181 outpatients (91 patients with PAF and 90 age- and gender-matched subjects without PAF) were analysed for their sinus rhythm. The CAVI was significantly higher in patients with PAF than in subjects without PAF (9.0±1.0 vs 8.7±0.8, p<0.01). In all subjects, the CAVI was significantly correlated with the left ventricular mass index (r=0.30, p<0.01), left atrial diameter (r=0.22, p<0.01), and augmentation index, a parameter of wave reflection (r=0.32, p<0.01), in addition to age, systolic blood pressure and pulse pressure. Logistic analysis demonstrated that the CAVI was independently associated with PAF even after adjustment for confounding factors. The adjusted OR of PAF was 1.8 for each unit increase in the CAVI (p=0.01). Conclusions Our finding suggests that increased arterial stiffness may be involved in the maintenance of AF.

Safety and Efficacy of Under-dosing Non-vitamin K Antagonist Oral Anticoagulants in Patients Undergoing Catheter Ablation for Atrial Fibrillation.

Background: Some patients with atrial fibrillation (AF) received underdoses of non-vitamin K antagonist oral anticoagulants (NOACs) in the real world. Underdosing is defined as administration of a dose lower than the manufacturer recommended dose. Objectives: To identify the efficacy and safety of underdosing NOACs as perioperative anticoagulation for atrial fibrillation ablation. Methods: We retrospectively analyzed patients who received rivaroxaban or dabigatran etexilate according to dosage: adjusted low dosage (reduced by disturbed renal function; n = 30), underdosage (n = 307), or standard dosage (n = 683). Non-vitamin K antagonist oral anticoagulants and dosing decisions were at the discretion of treating cardiologists. Results: Patients who received underdosed NOACs were older, more often female, and had lower body weight and lower renal function than those who received standard dosages. Activated clotting time at baseline in patients who received adjusted low dosage or underdosages was slightly longer than that in patients receiving standard dosages (156 ± 23, 151 ± 224, and 147 ± 24 seconds, respectively). Meaningful differences were not observed in other coagulation parameters. Adjusted low-, under-, and standard-dosing regimens did not differ in perioperative thromboembolic complications (0/30, 0.0%; 1/307, 0.3%; and 0/683, 0%, respectively) or major (0/30, 0.0%; 2/307, 0.6%; 3/683, 0.4%) and minor (1/30, 3.3%; 13/307, 4.2%; 25/683, 3.6%) bleeding episodes. When comparisons were performed for each NOAC, similar results were observed. Conclusions: With consideration of patient condition, age, sex, body weight, body mass index, and renal function, underdosing NOACs was effective and safe as a perioperative anticoagulation therapy for atrial fibrillation ablation. The therapeutic range of NOACs is potentially wider than manufacturer recommendations.BACKGROUND Some patients with atrial fibrillation (AF) received under-doses of non-vitamin K antagonist oral anticoagulants (NOACs) in the real world. Under-dosing is defined as administration of a dose lower than the manufacturer recommended dose. OBJECTIVES To identify the efficacy and safety of under-dosing NOACs as perioperative anticoagulation for AF ablation. METHODS We retrospectively analyzed patients who received rivaroxaban or dabigatran etexilate according to dosage: adjusted low-dosage (reduced by disturbed renal function; n = 30), under-dosage (n = 307), or standard-dosage (n = 683). NOACs and dosing decisions were at the discretion of treating cardiologists. RESULTS Patients who received under-dosed NOACs were older, more often female, and had lower body weight, and lower renal function than those who received standard-dosages. Activated clotting time at baseline in patients who received adjusted low- or under-dosages was slightly longer than that in patients receiving standard-dosages (156 ± 23, 151 ± 224, and 147 ± 24 seconds, respectively). Meaningful differences were not observed in other coagulation parameters. Adjusted low-, under-, and standard-dosing regimens did not differ in perioperative thromboembolic complications (0/30, 0.0%; 1/307, 0.3%; and 0/683, 0%, respectively), or major (0/30, 0.0%; 2/307, 0.6%; 3/683, 0.4%) and minor (1/30, 3.3%; 13/307, 4.2%; 25/683, 3.6%) bleeding episodes. When comparisons were performed for each NOAC, similar results were observed. CONCLUSION With consideration of patient condition, age, sex, body weight, body mass index, and renal function, under-dosing NOACs was effective and safe as a perioperative anticoagulation therapy for AF ablation. The therapeutic range of NOACs is potentially wider than manufacturer recommendations.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND) , where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

Adaptive-servo ventilation combined with deep sedation is an effective strategy during pulmonary vein isolation

AIMS Pulmonary vein isolation (PVI) by catheter ablation for atrial fibrillation (AF) requires suppression of patient restlessness by sufficient sedation in addition to maintaining stable respiration. We applied adaptive-servo ventilation (ASV) and examined the effects of ASV combined with deep propofol sedation on PVI using a NavX. METHODS AND RESULTS We analysed 75 paroxysmal AF (PAF) patients (62 ± 11 years; 53 men and 22 women) who underwent PVI for treatment of PAF using an ASV system combined with deep sedation (ASV group). Control patients included 75 consecutive PAF patients (62 ± 11 years; 51 men and 24 women) who underwent PVI just before introduction of the ASV system. Deep sedation was defined as a Ramsay sedation score of 6. The ASV group had a lower frequency of restless body movements compared with the control group during PVI (1.5 ± 0.7 vs. 7.8 ± 1.4 times, P < 0.01). The frequency of respiratory compensation and EnGuide alignment of catheter position by the NavX was lower in the ASV (4.2 ± 3.3 and 8.8 ± 7.1 times) than control group (7.1 ± 5.1 and 15.2 ± 10.0 times, P < 0.05 and <0.01, respectively). Consequently, significantly lower total electrical energy supply (48.7 ± 6.0 KJ) was required in the ASV than control group (64.5 ± 24.9 KJ, P < 0.01). Further, significantly shorter fluoroscopy and procedural times were observed in the ASV (28 ± 5 and 109 ± 25 min) than the control group (33 ± 6 and 141 ± 38 min, respectively, P < 0.01) and the AF recurrence rate was significantly lower in the ASV than the control group (12 vs. 25%, P < 0.01). CONCLUSION ASV combined with deep sedation is an effective strategy during PVI using the NavX in patients with PAF.

Circulating white blood cell count correlates with left ventricular indices independently of the extent of risk area for myocardial infarction after successful reperfusion.

Objective — To test the hypothesis that the circulating white blood cell (WBC) and neutrophil counts are related to left ventricular (LV) indices in patients with the same risk area for acute myocardial infarction (AMI), we examined 100 consecutive AMI patients who had the culprit lesion at segment 6 according to the American Heart Association classification and who underwent successful direct coronary angioplasty. Methods and results — The LV ejection fraction (LVEF), end-systolic volume (LVESVI) and end-diastolic volume index (LVEDVI) were obtained by left ventriculography performed 4 weeks after AMI onset. Univariate analysis disclosed that the counts of WBC and neutrophils on admission, and the maximal WBC count correlated negatively with LVEF (r = –0.46, p < 0.001; r = –0.54, p < 0.001 and r = –0.40, p < 0.001, respectively) and positively with LVESVI (r = 0.43, p < 0.001; r = 0.55, p < 0.001, and r = 0.30, p < 0.01, respectively). The counts of WBC and neutrophils on admission also correlated with LVEDVI (r = 0.28, p < 0.01 and r = 0.41, p < 0.001, respectively). Multivariate analysis with other clinical and angiographic factors revealed that the counts of WBC and neutrophils on admission correlated with LVEF (partial correlation coefficient, r = –0.37, p < 0.001 and r = –0.52, p < 0.001, respectively), with LVESVI (r = 0.34, p < 0.01 and r = 0.56, p < 0.001, respectively) and with LVEDVI (r = 0.28, p < 0.01 and r = 0.44, p < 0.001, respectively). The maximal WBC count also correlated with LVEF and LVESVI (r = –0.40, p < 0.001 and r = 0.21, p < 0.05, respectively). Conclusion — The present study revealed that the circulating WBC count correlated with function and volume of the successfully reperfused LV after AMI in patients with the same risk area for AMI, indicating that the WBC count needs to be taken into consideration as an independent factor affecting the LV indices.