Chiho Tokunaga

The minimum coronary artery diameter in which coronary spasm can be identified by synchrotron radiation coronary angiography

BACKGROUND Coronary vasospasm is defined as a temporary, intense narrowing of the coronary conduit artery. It brings about ischemic chest pain and becomes one of the causes of myocardial infarction. Coronary spasms are divided into two categories. One is the coronary spasm of the conduit artery and the other is the coronary microvascular spasm. Although coronary spasms are diagnosed with the images of coronary angiography, microvascular spasms cannot be diagnosed because of the limitations of conventional angiographic systems. However, synchrotron radiation coronary angiography (SRCA) can identify coronary arteries down to 100 microm in diameter in the beating heart and 50 microm in arrested heart. AIM The purpose of this study was to confirm whether microvascular spasms could be identified or not using SRCA, and then down that size identification was possible. METHODS The Langendorff perfusion system with isolated rat hearts was employed. Krebs-Henseleit solution (KH solution) was used as a perfusate. 10mM of 4-aminopyridine (4-AP: a voltage-gated potassium channel blocker; spasm inducer) was added to the KH solution and maintained for 5 min. SRCA was performed at pre-, during and 10 min after cessation of the KH solution with 4-AP. Coronary spasms were defined as a temporal 75% reduction of coronary arterial diameter. RESULTS AND CONCLUSION Multiple sizes of coronary arteries showed coronary spasms. The minimum stenosed coronary artery size was 100 microm. Since coronary microvascular spasms are seen in the arterioles (50-400 microm), coronary microvascular spasms may be diagnosed with the use of synchrotron radiation coronary angiography.

Palliative open heart surgery in an infant with factor VII deficiency

An infant with factor VII deficiency underwent palliative open heart surgery for pulmonary atresia with an intact ventricular septum. No references had been found on the management of this rare coagulation disorder in infantile cardiac surgery. We describe the peri- and postoperative management with a replacement therapy including a recombinant factor VIIa concentrate. We conclude that an appropriate replacement therapy is needed to control bleeding during open heart surgery with factor VII deficiency.

Complex coronary artery aneurysm

A 68-year-old female with no previous history of coronary artery disease, hypertension, or hyperlipidemia presented with abnormal electrocardiographic changes which was ST elevation in V1 and V2 lead. The electrocardiogramwas performed for regular medical checkup. An echocardiogram revealed an aneurysmal structure along the intraventricular septum (Figure 1A). A computed tomogram (CT) demonstrated a coronary artery aneurysm, 5.0 × 2.8 cm, with a 1.3 × 1.0-cm pseudoaneurysm (Figure 2A). A coronary angiogram revealed that the aneurysm appeared to arise from the left anterior descending (LAD) artery and was fed by a septal artery (Figure 1B). At the time of surgery, following institution of cardiopulmonary bypass and cardioplegic arrest, the feeding artery was identified and divided and each end closed with a running 6-0 polypropylene suture (Figure 3A). The aneurysm and pseudoaneurysm were opened and no fistulas or other vascular communications could be identified. The aneurysmal wall was obliterated with a running 3-0 prolene suture (Figure 3B). The patient tolerated the procedure and had no coronary ischemia. A postoperative CT scan showed a patent LAD without any aneurysmal changes (Figure 2B).

Troponin elevation after radiofrequency catheter ablation of atrial fibrillation: Relevance to AF substrate, procedural outcomes, and reverse structural remodeling

BACKGROUND Although radiofrequency ablation creates myocardial necrosis leading to troponin T (TnT) release into the systemic circulation, the significance of TnT elevation after atrial fibrillation (AF) ablation is unknown. OBJECTIVE To demonstrate a possible mechanism of reverse structural remodeling in the left atrium (LA) by evaluating postprocedural TnT elevation. METHODS This study included 106 patients with an enlarged LA (paroxysmal AF, n = 43; persistent AF, n = 63). All patients underwent pulmonary vein isolation alone in the index procedure. Left atrial volume indexed to body surface area (LAVi) was measured by echocardiography before ablation and 6 months after sinus rhythm restoration. Patients were divided into responders (n = 53) and nonresponders (n = 53) based on a cutoff value of 23% reduction in LAVi. The TnT level was measured 12 hours postprocedure. RESULTS LAVi decreased from 43 ± 13 to 33 ± 12 mL/m(2) (P < .0001). The TnT level was higher in responders than in nonresponders (1.31 ± 0.34 μg/L vs 0.88 ± 0.29 μg/L; P < .0001) and correlated linearly with percent reduction in LAVi (R = .54; P < .0001). Also in multivariate analysis, the TnT level was the only independent predictor for responders (odds ratio 90.1; 95% confidence interval 14.95-543.3; P < .0001). The TnT level in patients who required a repeat procedure (n = 30) was lower than that in patients who did not require a repeat procedure only in the persistent AF group (0.92 ± 0.38 μg/L vs 1.16 ± 0.37 μg/L; P = .01). CONCLUSION Greater elevation of the TnT level was related both to favorable outcomes after ablation and to greater reversal of structural remodeling. Postprocedural TnT level may be reflective of the preservation of healthy LA myocardium.

Effects of Landiolol Hydrochloride on Intractable Tachyarrhythmia After Pediatric Cardiac Surgery

BACKGROUND While β-blockers can be effective in controlling tachyarrhythmias after pediatric cardiac surgery, a negative inotropic influence sometimes complicates their use. Landiolol hydrochloride is a novel, ultra-short-acting β-blocker recently developed in Japan. The drug has higher β1:β2 selectivity ratio and a less negative inotropic effect. This study retrospectively evaluates the efficacy and safety of landiolol in the management of tachyarrhythmias after pediatric cardiac surgery. METHODS A retrospective analysis was performed on 312 consecutive patients undergoing surgery for congenital heart disease. Twelve patients were treated with landiolol for critical tachyarrhythmia. The mean age of patients was 28.7 ± 10.6 months. Five junctional ectopic tachycardia, 2 atrial flutters, 1 paroxysmal supraventricular tachycardia, 1 atrial fibrillation, 1 atrioventricular reciprocating tachycardia with Wolff-Parkinson-White syndrome and 2 excessive sinus tachycardia were treated. RESULTS The mean loading and maintenance doses were 11.3 ± 4.0 and 6.8 ± 0.9 μg/kg per minute, respectively. Rate control was achieved in all patients. Landiolol reduced the heart rate from 169.7 ± 11.4 to 127.7 ± 7.5 beats per minute (p < 0.05) while blood pressure did not significantly change. Tachyarrhythmias were converted to sinus rhythm in 70.0% of the cases and the average time needed to achieve heart rate reduction was 2.3 ± 0.5 hours. CONCLUSIONS Landiolol was efficacious in treating tachyarrhythmia in pediatric cardiac surgery. The desired negative chronotropic effect was achieved without significant hemodynamic compromise. The ultra-short half-life of landiolol provided rapid dose manipulation. This study suggests that landiolol is a promising option for the management of postoperative tachyarrhythmias in pediatric patients.

Surgical removal of infected pacemaker leads without cardiopulmonary bypass after failed extraction using the Excimer Laser Sheath Extraction System

With the growing number of cardiac pacemakers and internal cardioverter defibrillator implantations, problems with endocardial lead infection have been increasing. The newly developed Excimer Laser Sheath Lead Extraction System has been recognized as being highly useful for removing chronic infected leads. However, serious bleeding complications are a concern when this system is used. Here we report our experience with a 67-year-old man who was diagnosed with pacemaker endocarditis. Initially, lead removal was attempted using the Excimer Laser Sheath Extraction System, though this was abandoned because of severe adhesion of the leads and the junction of the supra vena cava (SVC) with the right atrium. Surgical removal of the leads was performed without using cardiopulmonary bypass and the leads were removed without any complications. During surgery, we found there was a silent perforation of the innominate vein brought about by the Excimer Laser Sheath System. Also, the junction of the SVC with the right atrium was thought to be an area potentially at high risk of perforation, because of a lack of surrounding tissue. It is our opinion that those who carry out procedures with the Excimer Laser Sheath System should understand the potential risk of perforation based on cardiac anatomy and should be prepared for lethal bleeding complications. Also, for emergent situations, we believe that close backup by a cardiovascular surgical team should be considered essential for performing the Excimer Laser Sheath Lead Extraction safely.

Anomalous Origin of the Right Coronary Artery From the Left Sinus of Valsalva in an Elderly Man Life-Threatening Worsening of Angina After Left Lung Lobectomy

A 77-year-old man underwent left lower-lung lobectomy for lung cancer in August 2009. He was free of angina before surgery. He presented to our hospital with exertional chest pain in September 2010. Exercise stress ECG revealed ST-segment depression in leads II, III, aVF, V5, and V6 with chest pain (Figure 1). Computed tomographic coronary angiography revealed a severe stenosis at the right coronary artery (RCA) ostium without atherosclerotic plaque that originated from the left sinus of Valsalva and coursed between the aortic root and the pulmonary artery (Figure 2). Compared with the prelobectomy chest computed tomography, the pulmonary artery was larger than before surgery (Figure 3). Estimated right ventricular systolic pressure measured by Doppler echocardiography was also higher than before surgery (32 versus 23 mm Hg). We thought that his worsening angina might be caused by extrinsic mechanical compression of the RCA between the aortic root and the dilated pulmonary artery after the left lower-lung lobectomy. Coronary artery angiography revealed an RCA with an anomalous origin from the left sinus …

A new technique of in vivo synchrotron radiation coronary microangiography in the rat

Background Previously, in our laboratory, synchrotron radiation coronary microangiography (SRCA) using Langendorff-perfused rat hearts could visualize a coronary artery of 50 µm in diameter. However, in vivo rat SRCA poses the problem of compromised temporal resolution due to the rapid heart rate of rats. Purpose To establish a simple method of in vivo rat SRCA with bradycardia induced by intravenous injection of adenosine triphosphate disodium hydrate (ATP). Material and Methods SRCA was performed at the Photon Factory of the High Energy Accelerator Research Organization (Tsukuba, Japan). Eight male Wistar rats were anesthetized. A catheter for injecting the contrast material was inserted into the carotid artery. Temporary bradycardia was induced by an intravenous bolus injection of 5 mg of ATP, and SRCA was performed immediately thereafter. Results After ATP administration, the average heart rate decreased from 388 to 73 beats per minute. As a result, we could detect a coronary artery as small as 45 µm in diameter. Conclusion Our SRCA system which has a high resolution of 9 µm per pixel could detect a coronary artery as small as 45 µm in diameter in the in vivo rat.

Kawashima Procedure After Staged Unifocalizations in Asplenia With Major Aortopulmonary Collateral Arteries

We report a Kawashima procedure (total cavopulmonary shunt) successfully carried out for asplenia syndrome, pulmonary atresia, and major aortopulmonary collateral arteries. At the age of 8, the patient underwent staged bilateral unifocalizations using confluent central pulmonary arteries concomitant with bilateral modified Blalock-Taussig shunts. As the result of an interrupted inferior vena cava with azygous continuation, the patient required a Kawashima procedure with augmentation of the central pulmonary arteries for definitive palliation 1 year later. Cyanosis, respiratory distress, and ventricular function improved.

Giant coronary artery aneurysm with pulmonary artery fistula in a patient on chronic hemodialysis.

The combination of coronary artery aneurysm and pulmonary artery fistula is extremely rare and its common cause is atherosclerosis. A 61-year-old woman presented with a giant coronary artery aneurysm with pulmonary artery fistula and intramyocardial calcifications of the left ventricle associated with progressive atherosclerosis due to chronic hemodialysis. The coronary artery aneurysm was resected under cardiopulmonary bypass because of hemodynamic instability due to restrictive cardiac dysfunction. The patients restrictive cardiac dysfunction was improved after aneurysm resection. Surgical resection should be considered for giant coronary artery aneurysm with restrictive cardiac dysfunction.