Tomoyuki Iwase

First International Summit on Thoracic Aortic Endografting: Roundtable on Thoracic Aortic Dissection as an Indication for Endografting

Address for correspondence and reprints: Shin Ishimaru, MD, The Department of Surgery II, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023 Japan. Fax: 81-3-33422827; Email: ishimaru@tokyo-med.ac.jp Endografting is increasingly applied for thoracic aortic aneurysms, but much remains to be clarified in regard to its proper applications and long-term efficacy. At present, the devices in use are mainly designed for the treatment of abdominal aortic aneurysms and thus do not necessarily meet the special requirements of the thoracic aorta. In this context, the first International Summit on Thoracic Aortic Endografting was held in Tokyo on March 2–3, 2001, to provide a forum for experts in the field to exchange information on techniques and results with thoracic aortic endograft repairs. During the summit, 428 participants from 109 institutions in 11 countries gathered to hold intensive and fruitful discussions. The following is a summary of the discussions and the consensus adopted at the Summit roundtable.

Treatment of acute inflammatory cardiomyopathy with intravenous immunoglobulin ameliorates left ventricular function associated with suppression of inflammatory cytokines and decreased oxidative stress

Although an autoimmune mechanism has been postulated for myocarditis and dilated cardiomyopathy, immunosuppressive agents had not been shown to be effective. Potential benefits of intravenous immunoglobulin (IVIg) in the therapy of patients with myocarditis and recent onset of dilated cardiomyopathy were reported. Also, experimental studies showed that IVIg is an effective therapy for viral myocarditis by antiviral and anti-inflammatory effects. Accordingly, in the current study, the effects of IVIg in the patients were investigated with the analyses of inflammatory cytokines and oxidative stress. Nine patients (six in myocarditis, three in acute dilated cardiomyopathy) were treated with high-dose intravenous IVIg (1-2 g/kg, over 2 days). All were hospitalized with New York Heart Association (NYHA) class III to IV heart failure, left ventricular ejection fraction (LVEF) <40%, and symptoms for <6 months at the time of presentation. Five patients were diagnosed using endomyocardial biopsy. LVEF determined by echocardiography improved from 19.0+/-7.5% (mean+/-S.D.) at baseline to 35.4+/-9.1% at follow up (12.2+/-5.8 days after the treatment) (P<0.01). C-reactive protein and plasma inflammatory cytokines (tumor necrosis factor-alpha and interleukin-6) were decreased by this treatment. In addition, plasma level of thioredoxin, which regulates the cellular state of oxidative stress, was decreased by the treatment. All nine patients improved functionally to NYHA class I to II, and were discharged without side-effects. There have been no subsequent hospitalizations for heart failure during the course of follow-up (3 months-4.5 years). LVEF improved 16% of EF in the patients with myocarditis and acute dilated cardiomyopathy with the reduction of cytokines associated with improvement of oxidative stress state by high-dose of IVIg. Thus, IVIg seems to be a promising agent in the therapy of acute inflammatory cardiomyopathy in view of not only suppression of inflammatory cytokines but a reduction of oxidative stress.

Transluminal endovascular branched graft placement for a pseudoaneurysm: Reconstruction of the descending thoracic aorta including the celiac axis

We I have previously reported a successful transluminal endovascular placement of a branched graft that had a sidearm extending into the left subclavian artery for repair of type B aortic dissection. The sidearm was properly positioned by catching and pulling back the free end of a detachable wire attached to its end by means of a gooseneck snare wire, which was percutaneously inserted through the left brachial artery. However, it is impossible to place sidearm grafts into the celiac axis and renal arteries in a similar manner. In this article, we describe a new method of inserting a sidearm into the celiac axis and report successful transluminal endovascular repair of a pseudoaneurysm with the use of the branched graft. A 73-year-old man with severe chronic renal failure requiring hemodialysis had previously undergone surgical repair of an aneurysm of the descending thoracic aorta. However, a pseudoaneurysm of the descending thoracic aorta resulting from dehiscence of the suture line at the proximal and distal anastomoses after composite graft surgery had continued to dilate, reaching 80 mm in diameter. Although surgical treatment was attempted, the effort was given up because of marked adhesions caused by a previous thoracotomy. He was admitted to our hospital for endovascular treatment of the pseudoaneurysm. The structure of the Inoue endovascular graft was previously described in detail. 2 The graft was constructed from a Dacron polyester fabric cylinder and the surface was supported by multiple rings of extra-flexible nickel titanium wire. The patient gave informed consent in conformance with the protocols approved by the institutional review board of Takeda Hospital. Endovascular grafting with the straight graft was performed on June 28, 1995. Although the proximal communication was completely obliterated after the procedure, the distal communication persisted because the distal orifice of the pseudoaneurysm was in close proximity to the celiac axis. Although transluminal embolization was

Clinical Application of Transluminal Endovascular Graft Placement for Aortic Aneurysms

BACKGROUND In recent years, transluminal endovascular graft placement techniques have been developed for the treatment of aortic aneurysms. We report our initial clinical experience with endovascular graft placement using a graft developed in our laboratory. METHODS The procedure was performed in 20 patients with a diagnosed aortic aneurysm. The graft is constructed from a Dacron cylinder, and the surface of the graft is supported with multiple rings of extraflexible wire. After the compactly folded graft is delivered through the sheath to the predetermined target point, the graft is deployed and then pressed against the vessel by balloon inflation. Straight graft insertion was attempted in 10 patients, bifurcated graft insertion in 8, and branched graft insertion in 2. RESULTS Graft placement was successful in 19 of the patients and unsuccessful in 1. There were no cases of graft migration, aneurysm rupture, or graft destruction during a mean follow-up period of 9 months. CONCLUSIONS Initial clinical results demonstrated the efficacy and safety of endovascular graft placement using this graft.

Relation between preexistent coronary collateral circulation and the incidence of restenosis after successful primary coronary angioplasty for acute myocardial infarction.

OBJECTIVES The purpose of this study was to test the hypothesis that the incidence of restenosis after primary percutaneous transluminal coronary angioplasty for acute myocardial infarction is largely influenced by the preexistent coronary collateral circulation to the infarct-related coronary artery. BACKGROUND The occurrence of restenosis after coronary angioplasty is the most serious limitation of this procedure. However, prediction of restenosis is difficult. Severe preexistent stenosis of the infarct-related coronary artery causing the development of collateral circulation may result in a high frequency of restenosis. METHODS The study group consisted of 152 consecutive patients undergoing primary coronary angioplasty within 12 h after the onset of a first acute myocardial infarction. Of this group, 124 patients were angiographically followed up during the convalescent period of infarction and were classified into two groups according to the extent of preexistent collateral circulation to the infarct-related coronary artery. RESULTS Restenosis occurred in 26 (38%) of 69 patients with poor or no collateral circulation (group A) in contrast to 35 (64%) of 55 patients with good angiographic collateral circulation (group B, p < 0.005). The frequency of preinfarction angina was significantly lower (p < 0.05) in group A (26% [18 of 69]) than in group B (44% [24 of 55]). CONCLUSIONS These findings indicate that the presence of well developed collateral circulation to the infarct-related coronary artery predicts a higher frequency of restenosis after primary coronary angioplasty. The difference in restenosis rates observed between the patients with and without good collateral circulation probably reflects the impact of underlying severity of stenosis on the long-term outcome after coronary angioplasty.

Transluminal repair of an infrarenal aortoiliac aneurysm by a combination of bifurcated and branched stent grafts

Transfemoral endovascular repair with a combination of bifurcated and branched stent grafts enables aortoiliac reconstruction with internal iliac perfusion preserved. We report a case of successful endovascular repair of aortoiliac aneurysm with use of a bifurcated and branched stent‐graft. Cathet. Cardiovasc. Intervent. 47:491–494, 1999.

Fate of Collateral Vessels After Successful Coronary Angioplasty in Patients With Effort Angina

OBJECTIVES The purpose of the present study was to evaluate whether severe restenosis after percutaneous transluminal coronary angioplasty (PTCA) promotes collateral development and whether successful dilation regresses collateral vessels. BACKGROUND It is well known that in the presence of severe coronary stenosis, native collateral arterioles mature to small coronary arteries with several layers of smooth muscle cells. However, it remains unclear whether well developed collateral vessels regress after removal of coronary stenosis. METHODS The study group comprised 41 patients who underwent elective PTCA for effort angina due to single-vessel disease, followed by repeat PTCA to treat restenosis. We classified the patients into three groups depending on the change in baseline Thrombolysis in Myocardial Infarction (TIMI) flow grade of the ischemia-related artery at initial and repeat PTCA, and we compared the extent of ST segment elevation at 1 min of the first balloon inflation between the two procedures. The average interval from initial to repeat PTCA was 125 days. RESULTS The three patient groups comprised group A, 12 patients with decreased flow grade because of severe coronary restenosis; group B, 12 patients with increased flow grade who had severe initial stenosis and relatively mild restenosis; and group C, 17 patients with unchanged flow grade. In the presence of comparable rate-pressure products at initial and repeat PTCA, patients in group A had significantly greater ST segment elevation (p < 0.01) at initial than at repeat PTCA (mean +/- SD 0.42 +/- 0.31 vs. 0.13 +/- 0.22 mV). In group B, ST segment elevation was significantly less at initial than at repeat PTCA (0.13 +/- 0.25 vs. 0.19 +/- 0.17 mV, p < 0.05), and in group C, it was comparable at the two procedures (0.37 +/- 0.32 vs. 0.35 +/- 0.33 mV, p = 0.50). CONCLUSIONS These findings indicate that severe restenosis after PTCA promotes collateral development and that successful dilaton regresses collateral vessels during a relatively short period of time.

Dependence of Doppler echocardiographic transmitral early peak velocity on left ventricular systolic function in coronary artery disease

The influence of systolic function on pulsed Doppler echocardiographic transmitral flow velocity patterns was assessed before and after postextrasystolic (PES) potentiation in 12 normal subjects (control group) and in 25 patients with previous healed myocardial infarction (MI) group. Simultaneous high-fidelity left ventricular pressure measurements were performed in all patients. A programmed single-coupled right ventricular extrasystole was induced during echocardiographic and subsequent cineangiocardiographic recordings. Adequate angiograms for volumetric analysis in both baseline and PES beats were obtained in 23 patients (7 in the control group and 16 in the MI group). PES potentiation of contraction was more pronounced in the MI group than in the control group. PES changes in ejection fraction, stroke volume and end-systolic volume were significantly greater in the MI group than in the control group (11 vs 5%, p less than 0.005; 15 vs 5 ml/m2, p less than 0.005; and -13 vs -4 ml/m2, p less than 0.01, respectively). In contrast, PES potentiation prolonged the time constants of left ventricular pressure decline derived from exponential curve fits with a zero (Tw) and non-zero (Tb) asymptote pressure in the MI group to the same extent as in the control group (4 vs 5 ms, difference not significant [NS], and 9 vs 11 ms, NS, respectively). In the PES beat, peak E velocity remained unaltered (48 vs 49 cm/s, NS) in the control group, whereas it increased significantly (p less than 0.0001) from 47 to 51 cm/s in the MI group.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of long-term left internal thoracic artery graft patency by exercise Doppler echocardiography

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Slope of the end-systolic pressure-volume relation derived from single beat analysis is not always sensitive to positive inotropic stimuli in humans

Single beat estimation of the slope of the end-systolic pressure-volume relation assumes symmetric left ventricular pressure increase and decay and requires extrapolation of peak isovolumic developed pressure (Pmax) from the left ventricular pressure curve of an ejection contraction. To test the sensitivity of this slope to positive inotropic stimuli, biplane cineangiocardiography and simultaneous high-fidelity left ventricular pressure measurements were performed in 50 patients with heart disease. The end-systolic pressure-volume relations were assessed under baseline conditions and during norepinephrine infusion (n = 19) or after postextrasystolic potentiation (n = 24), or both (n = 7). Norepinephrine did not change left ventricular end-systolic volume despite significant elevations of end-systolic pressure. Postextrasystolic potentiation significantly decreased end-systolic volume in association with an unaltered left ventricular end-systolic pressure. The potentiation significantly decreased the pressure half-time of contraction, an index of the speed of the left ventricular pressure increase, while it increased the pressure half-time of relaxation, an index of the speed of the pressure decline, indicating asymmetric pressure increase and decay. The slope of the end-systolic pressure-volume relation increased from 3.3 to 4.4 mm Hg/ml/m2 (p less than 0.001) during norepinephrine infusion. In contrast, despite an augmented contractility, the slope decreased significantly from 3.2 to 2.4 mm Hg/ml/m2 (p less than 0.0001) after the potentiation. The slope showed a high correlation with Pmax (r = 0.86, p less than 0.0001, n = 107). Thus, the slope of the end-systolic pressure-volume relation derived from single beat analysis is not always sensitive to inotropic interventions.(ABSTRACT TRUNCATED AT 250 WORDS)