Hiroshi Tomoeda

Inhibitory Effect of Milrinone on Cytokine Production After Cardiopulmonary Bypass

BACKGROUND It has been suggested that cyclic adenosine monophosphate-elevating agents suppress cytokine production. To evaluate the effects of milrinone, a phosphodiesterase III inhibitor, on cytokine production after cardiopulmonary bypass, we conducted a prospective randomized study. METHODS Twenty-four patients undergoing coronary artery bypass grafting were randomized to receive either milrinone treatment (milrinone, n = 12) or no milrinone treatment (control, n = 12). Administration of milrinone (0.5 microg x kg(-1) x min(-1)) was started after induction of anesthesia and was continued for 24 hours. Blood samples for determination of plasma cyclic adenosine monophosphate, tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and interleukin-8 levels were collected perioperatively. RESULTS No significant differences were observed in tumor necrosis factor-alpha and interleukin-8 levels between the groups. Interleukin-1beta and interleukin-6 levels after cardiopulmonary bypass were significantly (p < 0.05) lower in the milrinone group than in the control group. Plasma levels of cyclic adenosine monophosphate increased significantly (p < 0.05) after the administration of milrinone and the levels correlated inversely (r = -0.55, p < 0.01) with interleukin-6 levels. CONCLUSIONS The results indicate that milrinone suppresses cytokine production by elevating cyclic adenosine monophosphate levels in patients undergoing cardiopulmonary bypass. With its positive inotropic and vasodilator activities, milrinone may have antiinflammatory effects.

Obstruction of St. Jude Medical Valves in the Aortic Position: Plasma Transforming Growth Factor Type Beta 1 in Patients With Pannus Overgrowth

The study investigated the hypothesis that plasma transforming growth factor type beta 1 (TGF-beta1) initiated pannus overgrowth in cases with aortic prosthetic valve dysfunction (PVD). Patients with obstruction of an aortic St. Jude Medical valve in 26 cases (PVD group) and without obstruction in 48 cases (control group) were studied. Plasma TGF-beta1, the intensity of the prothrombin time-international normalized ratio (PT-INR), and the interruption of an oral anticoagulant medicine were conducted. Plasma TGF-beta1 levels in the PVD group (87.7 +/- 29.2 ng/mL) were significantly higher (P < 0.05) than in the control group (73.7 +/- 25.2 ng/mL). The interruption of an oral anticoagulant medicine in 54% of the PVD group versus 12% of the control group was identified (P < 0.001). The mean value of the PT-INR in the PVD group (1.75 +/- 0.30) and control group (1.75 +/- 0.30) was not significantly different (P = 0.82). In conclusion, elevated levels of plasma TGF-beta1 may play a role in pannus overgrowth.

Recurrent Mitral Regurgitation Due to Calcified Synthetic Chordae

We report a case of recurrent mitral regurgitation due to calcification of the expanded polytetrafluoroethylene sutures. According to pathologic findings, it was believed that due to the dystrophic calcification of the fibrous tissue covering the expanded polytetrafluoroethylene sutures, there was increased hyalinization, leading to sclerosis and shortening of the chordae. Calcification of expanded polytetrafluoroethylene sutures after mitral valve repair is a rare complication; however, careful follow-up should be needed because such change may occur in long-term periods after implantation.

Stroke in thoracic aortic surgery: outcome and risk factors.

The risk factors and the outcome of stroke in thoracic aortic surgery were studied in 127 patients (86 males, 41 females), aged 18 to 84 years (mean, 64 years), operated on between September 1994 and December 2000. There were 29 operations on the ascending aorta, 63 arch, 29 descending, 5 thoracoabdominal, and 1 extraanatomical bypass. Perioperative stroke occurred in 15 patients (12%). The risk factors for stroke were identified as preexisting chronic renal failure and femoral arterial cannulation. Hospital death occurred in 4 of the 15 cases (27%) of stroke and 7 of the 112 cases (6%) without stroke (p < 0.05). There were 18 late deaths during a mean follow-up period of 3.2 years (range, 1 month to 7.2 years). The 3-year survival rates were 43 ± 14% in the stroke patients and 85 ± 4% in the other patients. Actuarial survival, including during hospitalization, was lower in the stroke patients than in the other patients not only among those 70 years or older but also among all the patients (both p < 0.0001). Stroke occurring in thoracic aortic surgery is thus an important risk factor for early and late mortality, particularly in patients 70 years or older.

Doppler Echocardiographic Evaluation of Prosthetic Valves in Tricuspid Position

Doppler echocardiographic characteristics of 29 normally functioning prosthetic valves (23 mechanical, 6 biological) and 8 obstructed mechanical prostheses in the tricuspid position are reported. In normally functioning prostheses, peak velocity, mean pressure gradient, and pressure-half time were 1.25 ± 0.18 m·sec−1, 2.6 ± 1.1 mm Hg, and 122.6 ± 30.7 msec, respectively. Although no significant differences were seen in peak velocity and mean pressure gradient between mechanical and biological valves, the pressure half-time was significantly greater in biological valves. All normally functioning prostheses had a mean pressure gradient ⩽5.5 mm Hg and pressure half-time < 200 msec. In obstructed bileaflet valves, peak velocity was 1.66 ± 0.28 m·sec−1, mean pressure gradient was 6.1 ± 2.8 mm Hg, and pressure half-time was 265.8 ± 171.7 msec. These Doppler data were significantly greater than those in normally functioning valves where the mean pressure gradient was ⩽5.1 mm Hg and the pressure half-time was ⩽156 msec in all except one patient. Pathological obstruction of a tricuspid prosthesis can be strongly suspected in patients with a mean pressure gradient > 5.5 mm Hg and a pressure half-time > 200 msec on Doppler echocardiography.

Postoperative Left Ventricular Mass Regression After Aortic Valve Replacement for Aortic Stenosis

BACKGROUND Small valve size and prosthetic patient mismatch are both considered to have harmful effects on residual left ventricular hypertrophy after aortic valve replacement for aortic stenosis. In general, it is believed that the effective orifice area index of the prosthesis must not be less than 0.85 cm(2)/m(2) in order to avoid prosthetic patient mismatch. On the other hand, studies have shown that valve type and valve size had no effects on postoperative left ventricular mass (LVM). The objective of this report was to examine the relationships between patient characteristics or the prosthetic valve and postoperative LVM. METHODS To evaluate the factors that influence postoperative LVM, we formulated the hypothesis that postoperative LVM is proportional to the sum total of pressure at the prosthetic valve orifice and inner surface area of the left ventricle in systole. We present a conceptually new index for postoperative LVM and compare the index with postoperative LVM. RESULTS The results indicated a strong correlation between the new index and postoperative LVM six years after surgery (r(2) =0.67, p < 0.0001). As might be expected, LVM increased gradually as the value of the new index increased. CONCLUSIONS The results of the present study indicate that postoperative left ventricular hypertrophy can be avoided by preventing postoperative hypertension in patients without left ventricular dilatation and an effective orifice area index is greater than 0.77 cm(2)/m(2).

Microbubble generation in roller and centrifugal pumps

In order to investigate the difference in microbubble generation between roller and centrifugal pumps, this quantitative bench study was conducted. Using a mock circuit and fresh bovine blood, a roller pump or a centrifugal pump was run with 51/min of flow and 350 mm Hg of total pressure head. Microbubbles were produced by inflow tube occlusion (3 or 5s). Blood temperature was maintained at 25° and 36°C. Using a Doppler microbubble detector, the maximum diameter of the bubbles was monitored every 0.1s for 60s (total, 600 samples) at the prearterial filter (pump outflow side) and the postarterial filter sites. The number of microbubbles larger than 32μm were counted. The roller pump generated significantly more large microbubbles than the centrifugal pump. Substantial numbers of large microbubbles were encountered at the postfilter site, particularly when the roller pump was used. The centrifugal pump does not create excessive negative pressure by inflow occlusion; microbubble generation was less than that of the roller pump. Furthermore, since the centrifugal pump has a pressure discrepancy in the pump, small bubbles tend to stay around the center of the pump. This study confirmed that the centrifugal pump generated fewer microbubbles than the roller pump during inflow obstruction. Therefore, the centrifugal pump is safer in terms of microbubble generation. Additional care should be taken to prevent air emboli while using the roller pump because substantial numbers of microbubbles may go through the arterial filter.

Pulsatile Varicose Veins Secondary to Severe Tricuspid Regurgitation: Report of a Case Successfully Managed by Endovenous Laser Treatment.

We report a case of pulsatile varicose veins successfully managed by endovenous laser treatment (EVLT) of the great saphenous vein (GSV). A 77-year-old woman taking an anticoagulant was transferred to our hospital for pulsatile varicose veins complicated with repeated venous bleeding from an ulcer of her left lower leg. Doppler echocardiography showed severe tricuspid regurgitation, and duplex ultrasonography revealed an arterial-like pulsating flow in the saphenofemoral junction and along the GSV, but an arteriovenous fistula, obstruction of the deep veins, and the distal incompetent perforators were not detected. Because of a significant bleeding risk due to elevated venous pressure and anticoagulant therapy, EVLT was performed for the GSV, which resulted in the complete occlusion of the GSV and healing of the ulcer. EVLT presents a safe and useful therapeutic technique for pulsatile varicose veins in the limbs.

Emergent surgery for 3 aged patients who refused elective operation for thoracic aortic aneurysm

This report describes 3 aged patients undergoing emergent surgery who refused elective operation for a thoracic aortic aneurysm because of freedom from symptoms attributable to the aneurysm at the time of presentation. A 77-year-old woman with a thoracoabdominal aneurysm 57 mm in diameter at presentation had recurrent hemoptysis 12 months later. A 78-year-old man with a saccular type distal arch aneurysm 64 mm in diameter at presentation was transported with shock and hemothorax 27 months later. Another 82-year-old man with a saccular type distal arch aneurysm 60 mm in diameter at presentation was admitted with severe chest and back pain 36 months later. All of them underwent tube graft replacements of the aneurysm urgently and were discharged on foot. Aged patients with life-threatening events should not be denied surgical intervention because of excessive operative mortality and morbidity, even if they had previously refused elective surgery.

A Case of Unruptured Aneurysm of the Sinus of Valsalva.

症例は36歳女性. 5歳時に心室中隔欠損症 (VSD) の診断を受け経過観察中であった. 36歳時, 労作時の軽度の息切れと動悸を認めるようになったことから精査目的のため, 当科紹介となった. 心エコー検査では肺動脈弁直下に直径約1cmのVSDを認めたが, バルサルバ洞の瘤状の突出像は確認できなかった. 右室造影像では肺動脈弁直下の右室流出路に, 円形で大きさが1.0cm×1.5cmの陰影欠損を認め非破裂性バルサルバ洞動脈瘤 (今野分類I型) と診断し手術を施行した. 術後経過は良好で術後14日目の左室造影検査ではVSDは完全に閉鎖されバルサルバ洞動脈瘤もまったく造影されなかった. また, 診断には右室造影検査が有用であった.