Takahiro Manabe

Decreased Tissue Inhibitor of Metalloproteinase-2/Matrix Metalloproteinase Ratio in the Acute Phase of Aortic Dissection

PurposeAortic dissection is characterized by fragility of the tunica media, and matrix metalloproteinases (MMPs) are enzymes that degrade the extracellular matrix of the aorta. This study examines MMPs in patients with acute aortic dissection (AAD) in an attempt to elucidate the mechanisms of their actions.MethodsEnzyme-linked immunosorbent assays were used to measure the quantification of MMP-2, MMP-9, and the tissue inhibitor of metalloproteinase (TIMP)-2 in 30 patients with AAD, 12 patients with abdominal aortic aneurysm (AAA), and 16 control (CON) patients who underwent coronary artery bypass grafting.ResultsMMP-2 and TIMP-2 were significantly lower in the AAD group than in the CON group, at 36 ± 19 vs 58 ± 30 (P ≪ 0.01) and at 21 ± 25 vs 216 ± 130 (P ≪ 0.001), respectively. The TIMP-2/MMP-2 ratio was 3.7 ± 1.7 in the CON group and 0.9 ± 0.8 in the AAD group (P ≪ 0.001 vs CON), and the TIMP-2/MMP-9 ratio was 200 ± 170 in the CON group and 37 ± 80 in the AAD group (P ≪ 0.001 vs CON).ConclusionLow TIMP-2/MMP-2 and TIMP-2/MMP-9 ratios might play an important role in the onset of aortic dissection, when the tunica media becomes fragile with chronic breakage and degradation of the extracellular matrix.

Ultrasonography and Lung Mechanics Can Diagnose Diaphragmatic Paralysis Quickly

Diaphragmatic paralysis after cardiovascular surgery requires early diagnosis prior to extubation. The effectiveness of ultrasonography and a lung mechanics assessment was evaluated. Paralysis of the diaphragm was diagnosed when the diaphragm failed to move or moved in a cephalad direction during inspiration. It was diagnosed in 3 of 40 patients (7.5%) who underwent cardiovascular surgery from 1998 to 1999. Patients were extubated when all parameters met the extubation criteria, irrespective of the presence or absence of diaphragmatic paralysis. One patient required prolonged assisted ventilation and died from mediastinitis on the 35th postoperative day. The other 2 patients required assisted ventilation for an additional 1–3 days. Ultrasonography and a lung mechanics assessment are effective tools for the early diagnosis of diaphragmatic paralysis and assessment of respiratory function after cardiovascular surgery.

Reoperative coronary artery bypass grafting via a left thoracotomy and a small laparotomy without cardiopulmonary bypass: report of a case.

Abstract A 66-year-old woman with aortic stenosis underwent an aortic root replacement with a composite graft and coronary artery reconstruction 2 years before presentation. On coronary angiography performed 2 years after operation, saphenous vein graft (SVG) to right coronary artery and SVG to first diagonal branch had both become totally occluded. SVG to left anterior descending artery showed 75% stenosis on the heel side of the distal anastomosis. The patient underwent a second coronary artery bypass via a left thoracotomy (the left internal thoracic artery was anastomosed to the first diagonal branch by interposing it with the left radial artery) and a small laparotomy (the right gastroepiploic artery was anastomosed to the right coronary artery) without a cardiopulmonary bypass. This approach is preferable to avoiding both a resternotomy and cardiopulmonary bypass in patients requiring repeat surgery.