Kazuhiro Nishigami

Long-Term Prognosis of Patients With Type A Aortic Intramural Hematoma

Background—The long-term clinical course of patients with type B aortic intramural hematoma (IMH) and predictors for progression remains unknown. The difference of aortic pathology may have a different impact on clinical course compared with classic aortic dissection (AD). The purpose of this study was to investigate long-term clinical course and predictors of progression in patients with type B IMH. Methods and Results—Clinical data were compared retrospectively between 53 patients with acute type B IMH (IMH group) and 57 patients with acute type B AD (AD group). All patients were treated initially with medical therapy. Two patients in IMH group and 14 patients in AD group underwent surgical repair because of aortic enlargement. The in-hospital mortality rate in IMH group was significantly lower than that in AD group (0% and 14%, P =0.006). Mean follow-up periods were 53±43 months, which revealed 3 and 5 late deaths, respectively. Eleven patients with IMH showed progression (development of aortic dissection or aortic enlargement) in follow-up imaging study. The actuarial survival rates in IMH group were 100%, 97%, and 97% at 1, 2, and 5 years, which were significantly higher than those in AD group (83%, 79%, and 79%) (P =0.009). Multivariate analysis identified age >70 years and new appearance of an ulcerlike projection as the strongest predictors of progression in patients with IMH. Conclusions—Patients with type B IMH have better long-term prognosis than patients with AD. Older age and appearance of an ulcerlike projection are predictive for progression in patients with type B IMH.

Unblinded Pilot Study of Autologous Transplantation of Bone Marrow Mononuclear Cells in Patients With Thromboangiitis Obliterans

Background— The short-term clinical benefits of bone marrow mononuclear cell transplantation have been shown in patients with critical limb ischemia. The purpose of this study was to assess the long-term safety and efficacy of bone marrow mononuclear cell transplantation in patients with thromboangiitis obliterans. Methods and Results— Eleven limbs (3 with rest pain and 8 with an ischemic ulcer) of 8 patients were treated by bone marrow mononuclear cell transplantation. The patients were followed up for clinical events for a mean of 684±549 days (range 103 to 1466 days). At 4 weeks, improvement in pain was observed in all 11 limbs, with complete relief in 4 (36%). Pain scale (visual analog scale) score decreased from 5.1±0.7 to 1.5±1.3. An improvement in skin ulcers was observed in all 8 limbs with an ischemic ulcer, with complete healing in 7 (88%). During the follow-up, however, clinical events occurred in 4 of the 8 patients. The first patient suffered sudden death at 20 months after transplantation at 30 years of age. The second patient with an incomplete healing of a skin ulcer showed worsening of the lesion at 4 months. The third patient showed worsening of rest pain at 8 months. The last patient developed an arteriovenous shunt in the foot at 7 months, which spontaneously regressed by 1 year. Conclusions— In the present unblinded and uncontrolled pilot study, long-term adverse events, including death and unfavorable angiogenesis, were observed in half of the patients receiving bone marrow mononuclear cell transplantation. Given the current incomplete knowledge of the safety and efficacy of this strategy, careful long-term monitoring is required for future patients receiving this treatment.

Tight heart rate control reduces secondary adverse events in patients with type B acute aortic dissection.

Background— Although type B aortic dissection has been treated with β blockers to lower the arterial blood pressure (BP), there has been little evidences about reduction in heart rate (HR). We assessed whether tight HR control improved the outcome of medical treatment in patients with aortic dissection. Methods and Results— From 1997 to 2005, 171 patients with acute aortic dissection medically treated and controlled to lower BP under 120 mm Hg were enrolled. Based on the average HR at 3, 5, and 7 days after the onset, patients were divided into tight HR (<60 beat per minute) control group (32 patients; mean HR of 56.6±3.1 beat per minute) and conventional HR (≥60 beat per minute) control group (139 patients; mean HR of 71.7±8.2 beat per minute). We compared the frequency of aortic events including late organ or limb ischemia, aortic rupture, recurrent dissection, and aortic expansion of >5 mm, and surgical requirement between two groups. During a median follow-up of 27.0 months, late organ or limb ischemia, aortic rupture, recurrent dissection, pathological aortic expansion, and aortic surgery occurred in 0, 8, 14, 39, and 26 patients, respectively. Reduction in aortic events was observed in tight HR control group (12.5%) compared to conventional HR control group (36.0%), (Odds ratio: 0.25, C.I.: 0.08 to 0.77, P<0.01). Conclusions— The present study demonstrated that tight heart rate control improved the outcome of medical treatment in patients with aortic dissection.

Renal Function in Patients with Abdominal Aortic Aneurysm

Aims: Renal dysfunction occurs occasionally after the repair of abdominal aortic aneurysm (AAA), and preoperative renal function is considered as one of the potential causes. The present study was designed to evaluate and compare renal function and risk factors of AAA patients with those of hypertensive patients. Methods: We prospectively examined 95 patients with AAA and 72 patients with essential hypertension (HT) without other cardiovascular diseases (CVD). Renal function, urinary albumin excretion (UAE) and renal scintigraphy were compared. Kidney size was calculated using ultrasonography. Results: Serum creatinine and creatinine clearance in AAA patients was worse than in HT patients. Smoking status was more apparent in AAA patients. Renal artery stenosis occurred in 8 patients with AAA. Renal scintigraphy showed normal function in 19%, hypofunction in 69% and severe dysfunction in 12% of the AAA patients, and normal function in 42% and hypofunction in 58% of the HT patients (p < 0.0001). Multivariate linear regression analysis showed that renal function was related to age, UAE, CVD, smoking status and kidney size for all patients, UAE, CVD, smoking status and kidney size for AAA patients, and age and kidney size for HT patients. Conclusion: Renal function of AAA patients was worse than HT patients without other CVD. The risk factors for renal dysfunction were different between AAA and HT patients. These preoperative conditions may relate to the postoperative renal dysfunction seen in AAA patients.

Impact of shear stress and atherosclerosis on entrance-tear formation in patients with acute aortic syndromes

Weak aortic media layers can lead to intimal tear (IT) in patients with overt aortic dissection (AD), and aortic plaque rupture is thought to progress to penetrating atherosclerotic ulcer (PAU) with intramural hematoma (IMH). However, the influences of shear stress and atherosclerosis on IT and PAU have not been fully examined. Ninety-eight patients with overt AD and 30 patients with IMH and PAU admitted to our hospital from 2002 to 2007 were enrolled. The greater curvatures of the aorta, including the anterior and right portions of the ascending aorta and anterior portion of the aortic arch, were defined as sites of high shear stress. The other portions of the aorta were defined as sites of low shear stress based on anatomic and hydrodynamic theories. Aortic calcified points (ACPs) were manually counted on computed tomography slices of the whole aorta every 10 mm from the top of the arch to the abdominal bifurcation point. IT was more often observed at sites of high shear stress in overt AD than in PAU (73.5 vs 20.0 %, P < 0.0001). Significantly more ACPs were present in PAU than in overt AD (18.6 ± 8 vs 13.3 ± 10, P = 0.007). The present study suggests that high shear stress and less severe atherosclerosis could induce the occurrence of an IT, thereafter progressing to overt AD, and that low shear stress and more severe atherosclerosis could proceed to PAU with IMH. These findings may help to identify the entrance-tear site.

Facilitation of Localized conduction block with procainamide during entrainment of sustained ventricular tachycardia

Intravenous administration of procainamide is widely used for the management of ventricular tachycardia (VT). Although its efficacy has been clinically established,’ the precise mechanism by which the drug interrupts VT still remains unclear. An experimental study on VT induced in the canine myocardial infarction model has suggested that a class I antiarrhythmic drug (lidocaine) causes conduction block preferentially within the reentry circuit and this interrupts the tachycardia.2 We recently suggested3 that transient entrainment of a tachycardia allows a selective examination of antiarrhythmic drug effect on the area of slow conduction within the reentry circuit of VT. This report presents data that suggest the possible mechanism of action of procainamide in its slowing and interruption of VT in man.

Effects of antecedent anginal episodes and coronary artery stenosis on left ventricular function during coronary occlusion

We evaluated the effects of antecedent anginal episodes and coronary artery stenosis on left ventricular function during coronary occlusion and the role of collateral filling in 33 patients with angina pectoris who underwent angioplasty. Wall motion abnormalities were investigated by echocardiography and classified into hypokinesia and akinesia. Collateral filling during angioplasty was evaluated by using a second artery catheter. Akinesia was observed as follows: 24% of the patients had > 30 anginal episodes, 38% had 5 to 30, and 87% of the patients had < 5 (p < 0.01); 12% of patients had a lesion of 99%, 47% had a lesion of 90%, and 83% had a lesion of 75% (p < 0.05). Akinesia was observed in none of the patients with grade 3 collaterals, 57% with grade 2, and 67% with grade 1 or 0 (p < 0.01). These observations suggest that the patients with antecedent frequent anginal episodes and severe coronary stenosis have less left ventricular dysfunction during coronary occlusion. This finding may be the result of more extensive collateral development.

Brain Embolism Caused by a Mobile Aortic Thrombus with Iron Deficiency Anemia

a Cerebrovascular and b Cardiovascular Divisions, Department of Medicine, and c Department of Radiology, National Cardiovascular Center, Osaka , Japan netic resonance imaging (CMRI) revealed a club-shaped fl oating mass ( fi g. 1 c), which was attached to the wall of the ascending aorta, but there were no abnormalities on the internal surface of the aorta, including the attachment of the mass. Extensive examinations were made to search for a cause of the IDA, but no abnormality was detected except for internal hemorrhoids. Her IDA improved with blood transfusion, and heparin administration was started. On day 19, the mass was no longer detected on TEE and CMRI. The plasma levels of thrombin-antithrombin III complex and D-dimer normalized. The patient’s hospital course was uneventful. She became used to walk with a cane. She was discharged from hospital on warfarin therapy. One year after the stroke, warfarin sodium was switched to aspirin. Reexamination of her PSA showed it improved to the normal range (76%). During 2 years of follow-up, the patient had no recurrence of stroke, thrombophilia or IDA. Patient 2. A 41-year-old housewife was admitted because of sudden onset of dysarthria and right-sided hemiplegia. Her medical history included epimenorrhagia since the age of 20 years. The patient had no established risk factors associated with cardiovascular diseases except for smoking. Her uncle had an ischemic stroke. On physical examination, her body mass index was 24, the pulse was regular (64/min), and the blood pressure was 128/64 mm Hg. Her palpebral conjunctiva was pale, suggesting anemia. She had mild Atherosclerotic lesions at the aortic arch are recognized as potential sources of embolic stroke [1] . There were some reports of embolic stroke caused by a mobile thrombus located at the aortic arch (MTAA) [2–5] . Although almost all these patients had marked atherosclerotic changes, a few reports demonstrated that an MTAA was not accompanied by atherosclerotic changes and had no defi nite etiology [4, 5] . Furthermore, previous studies suggested an association between thrombogenesis and anemia [6, 7] . We report 2 female patients with iron defi ciency anemia (IDA) who developed brain embolisms caused by an MTAA without having atherosclerotic changes in the aortic arch.

Point-of-care echocardiography for aortic dissection, pulmonary embolism and acute coronary syndrome in patients with killer chest pain: EASY screening focused on the assessment of effusion, aorta, ventricular size and shape and ventricular asynergy.

Focus assessed transthoracic echocardiography and focused cardiac ultrasound are point-of-care echo protocols for the evaluation of cardiac disease in the emergency room; however, these protocols may not adequately assess aortic dissection, pulmonary embolism, and acute coronary syndrome in patients with killer chest pain. Here, I present an echocardiography protocol focused on screening for these critical cardiovascular diseases. This protocol (termed EASY screening) consists of the assessment of effusion in the pericardial space, aortic abnormalities, the size and shape of the ventricles and asynergy of the left ventricle. Aortic dissection is suggested by positive findings for effusion and/or abnormal aortic findings. Pulmonary embolism is suggested by a dilated right ventricle and a D-shaped left ventricle in the short-axis view. Acute coronary syndrome is suggested by asynergy of left ventricular wall motion. EASY screening may facilitate the assessment of aortic dissection, pulmonary embolism and acute coronary syndrome in patients presenting to the emergency room with killer chest pain.

Simultaneous examination of the aorta in echocardiography of patients with coronary artery disease

The majority of aortic aneurysms are asymptomatic and are discovered incidentally on routine physical examination or on imaging studies for other indications [1], although the rupture of the aortic aneurysm can cause uncontrolled hemorrhage and rapid circulatory collapse. Atherosclerosis has been considered the underlying cause of aortic aneurysms, and the concomitant disorder of aortic aneurysm and coronary artery disease can be frequently observed [2]. Echocardiography is a basic modality to assess patients with coronary artery disease and can be used for the screening of aortic aneurysm. I would like to recommend the simultaneous examination of the aorta in the echocardiography of patients with coronary artery disease and propose the following screening method for aortic aneurysms. (1) Superior intercostal view (Fig. 1): left parasternal approach is a standard method for the long-axis view of the left ventricle, atrium, and proximal ascending aorta. The approach from the superior intercostal space can visualize the proximal to mid-portion of the ascending aorta. (2) Small-scale longaxis view (Fig. 2): the descending aorta can be seen behind the left atrium in the parasternal view of echocardiography by adjusting the window depth. (3) Subxiphoid view: abdominal aorta can be seen from subxiphoid and abdominal approaches. (4) Suprasternal view (Fig. 3): aortic arch to proximal descending aorta can be illuminated from the suprasternal approach on the ‘‘sniff’’ and supine position. These approaches may be recalled as the ‘‘four Ss’’. The routine evaluation of the aorta in echocardiography must make the time required for aortic echo shorter. Quick aortic echo using the four S approaches will be able to play an important role not only in the search for aortic aneurysm, but also in the evaluation of acute aortic dissection in the emergency room.