Takashi Ino

Influence of patent false lumen on long-term outcome after surgery for acute type A aortic dissection

OBJECTIVEnThe fate of the dissected distal aorta after surgery for acute type A aortic dissection has not been fully understood. We assessed the influence of a residual patent false lumen on long-term outcomes.nnnMETHODSnTwo hundred eighteen patients underwent emergency surgery for DeBakey type I or IIIb retrograde acute type A aortic dissection (1997-2006). Aortic arch replacement was performed in selected patients whose entry site was in or extended into the aortic arch. In-hospital mortality was 7.3% (16/218), and 193 survivors (mean age 62 years) underwent enhanced computed tomography within 1 month after the operation. These patients were divided into two groups according to the status of the false lumen, whether patent (n = 124) or thrombosed (n = 69). In each group, segment-specific aortic growth rate, distal reoperation, and late survival were examined.nnnRESULTSnGrowth rate was determined in 139 (72.0%) patients who underwent serial computed tomography. Average growth rate in the patent group was greater than that in the thrombosed group (aortic arch [1.1 vs -0.41 mm per year; P = .005], proximal descending aorta [1.9 vs -0.71 mm per year; P <.001], and distal descending aorta [1.3 vs -0.70 mm per year; P = .002]). However, growth was slow (<1 mm per year) in about 50% of patients in the patent group. There was no significant difference in distal reoperation or late survival between the two groups.nnnCONCLUSIONSnThe patent false lumen influences postoperative aortic enlargement. However, with careful follow-up, a favorable prognosis is expected even for patients with a residual patent false lumen.

Platelet dysfunction in acute type A aortic dissection evaluated by the laser light-scattering method

OBJECTIVESnPlatelet dysfunction contributes to bleeding tendency in acute type A aortic dissection. Particle counting by new laser light-scattering methods more accurately quantifies changes in the number of different-sized platelet aggregates than do conventional optical density methods. We studied platelet aggregation kinetics and patterns of aggregation deficiency in acute-phase aortic dissection with laser light scattering.nnnMETHODSnBlood from 20 acute type A aortic dissection patients undergoing surgery was sampled during acute (9.1 +/- 6.8 hours from onset) and chronic (postoperative day 20, control) phases of aortic dissection. Platelet count and aggregability were assessed by optical density and laser light-scattering methods after aggregation was induced (addition of 2.0 microg/mL collagen to samples).nnnRESULTSnOptical density showed significant reduction in acute-phase platelet aggregation (acute vs chronic: 65 +/- 27% vs 77 +/- 17%, P <.03). Laser light scattering showed significant reduction in medium (25-50 microm) and large (50-70 microm) but not small aggregate (9-25 microm) generation (acute vs chronic: small, 1.2 +/- 0.6 x 10(7) vs 1.5 +/- 1.0 x 10(7), NS; medium, 0.6 +/- 0.3 x 10(7) vs 1.1 +/- 0.5 x 10(7), P <.001; large, 1.4 +/- 1.2 x 10(7) vs 2.6 +/- 1.7 x 10(7), P <.001). Acute- versus chronic-phase platelet counts were significantly decreased (1.7 +/- 0.1 x 10(5)/microL vs 3.6 +/- 0.3 x 10(5)/microL, P <.001).nnnCONCLUSIONSnPlatelet aggregation is suppressed in acute-phase aortic dissection. This suppression does not occur in the initial phase of small aggregate formation; rather, it occurs during the conglomeration of small aggregates into larger aggregates.

The 17-mm St. Jude Medical Regent Valve Is a Valid Option for Patients With a Small Aortic Annulus

BACKGROUNDnWhen aortic valve replacement is performed in patients with a small aortic annulus, prosthesis-patient mismatch is of concern. Such prosthesis-patient mismatch may affect postoperative clinical status and survival. We investigated the outcomes of isolated aortic valve replacement performed with a 17-mm mechanical prosthesis in patients with aortic stenosis.nnnMETHODSnTwenty-three patients with aortic stenosis (mean age, 74.6 +/- 6.3 years) underwent isolated aortic valve replacement with a 17-mm St. Jude Medical Regent prosthesis. Mean body surface area was 1.41 +/- 0.13 m(2). Preoperative echocardiography yielded a mean aortic valve area of 0.36 +/- 0.10 cm(2)/m(2), a mean left ventricular-aortic pressure gradient of 68.4 +/- 25.3 mm Hg, and a mean left ventricular mass index of 200 +/- 69 g/m(2).nnnRESULTSnThere was no operative mortality, and there were no valve-related events. Echocardiography at 14.0 +/- 10.0 months after aortic valve replacement showed a significant increase in the mean effective orifice area index (0.95 +/- 0.24 cm(2)/m(2)), decrease in the mean left ventricular-aortic pressure gradient (17.4 +/- 8.2 mm Hg), and decrease in the mean left ventricular mass index (124 +/- 37 cm(2)/m(2)). Prosthesis-patient mismatch (effective orifice area index < 0.85 cm(2)/m(2)) was present in 8 patients at discharge. In these patients as well as in those without prosthesis-patient mismatch, the left ventricular mass index decreased remarkably during follow-up.nnnCONCLUSIONSnAortic valve replacement with a 17-mm Regent prosthesis appears to provide satisfactory clinical and hemodynamic results in patients with a small aortic annulus. Remarkable left ventricular mass regression during follow-up was achieved irrespective of the effective orifice area index at discharge.

Perfusion through the dorsalis pedis artery for acute limb ischemia secondary to an occlusive arterial cannula during percutaneous cardiopulmonary support

Percutaneous cardiopulmonary support (PCPS) is a powerful resuscitation tool for patients in cardiogenic shock. The femoral artery is generally used for arterial access; however, vascular complications, particularly in atherosclerotic arteries, can occur. Although such complications occur infrequently, they can be fatal. We describe the case of a 75-year-old woman who required extended PCPS for cardiogenic shock secondary to coronary spasm after on-pump beating coronary artery bypass grafting. Limb ischemia occurred because of an occlusive cannula, and distal perfusion with a 20G elastic intravenous catheter inserted into the dorsalis pedis artery resolved the ischemia. The catheter was connected to the side port of an oxygenator and provided distal limb perfusion during PCPS. This technique appears to be useful in treating limb ischemia and may have application in patients with arterial occlusive disease who are dependent on mechanical support.

Chronic type A aortic dissection associated with Listeria monocytogenes infection.

A previously healthy 77-year-old woman with a 4-week history of back pain and fever was admitted to our hospital for chronic type A aortic dissection. The aortic arch was enlarged to 7.5 cm in diameter, and the large dissecting aortic aneurysm involved all three branches of the aortic arch and compressed the trachea. Laboratory tests showed an increased C-reactive protein level (10.5 mg/dl). Blood cultures performed upon admission were negative. Progression of the symptoms suggested the possibility of impending aneurysm rupture. The patient underwent urgent total arch replacement, and cultures of samples obtained from the aortic wall during surgery were positive for Listeria monocytogenes. Two months after surgery, advanced rectal cancer was diagnosed. It is believed that the rectal cancer predisposed the patient to development of an arterial infection associated with L. monocytogenes.

Extracardiac aneurysm of the interleaflet triangle above the aortic-mitral curtain due to infective endocarditis of the bicuspid aortic valve

A previously healthy 33-year-old man presented to our hospital with fever, left hemiparalysis, motor aphasia, and clouding of consciousness. Echocardiography revealed vegetation attached to the bicuspid aortic valve as well as an aneurysm originating below the annulus. Head computed tomography showed multiple infarctions. Under the diagnosis of infective endocarditis and perivalvular aneurysm, operation was performed because of the risk of further embolization. Operative findings showed an extracardiac aneurysm of the interleaflet triangle above the aortic-mitral curtain. Because there was no sign of active inflammation, the orifice was closed with an autologous pericardial patch, and the aortic valve was replaced with a mechanical valve. We should be aware of extracardiac aneurysm of the interleaflet triangle when dealing with infective endocarditis, which should be operated as soon as it is found because of the risk for extracardiac aneurysmal rupture.

Infected left atrial myxoma with mitral valve endocarditis.

We report a rare case of infected left atrial myxoma associated with mitral valve endocarditis. The tumor and a small amount of vegetative growth on the anterior mitral leaflet were surgically excised. Subsequent antibiotic therapy may have prevented the infection from recurring. Histological findings showed myxoma cells embedded in mucinous stroma at the tumor base and an organized thrombus with bacterial colonization at the tumor tip.

Early postoperative aortic rupture following surgery for acute type A aortic dissection

We report our experience with patients who died of early aortic rupture following surgical treatment for acute type A aortic dissection in a consecutive series of 324 patients who underwent surgery for this condition between 1991 and 2007. In-hospital mortality rate was 9.9% (32/324), and seven patients (two men, mean age, 67 years) died of postoperative aortic rupture. Rupture sites were the proximal aorta in two and distal aorta in five patients. Surgical procedures included ascending aorta replacement in six and ascending aorta plus aortic arch replacement in one. The common characteristics of the two patients with proximal aortic rupture were preoperative aortic insufficiency, intraoperative bleeding from the proximal stump, and high blood pressure before the rupture. In contrast, the distal aortic ruptures occurred in patients with uncomplicated postoperative courses, with three distal aortic ruptures occurring on the inpatient ward. The only common characteristic of the distal aortic ruptures was residual patent false lumen (80%, 4/5 patients), the other patient had a large pre-existing aneurysm in the descending thoracic aorta. Careful postoperative management, including strict blood pressure control, is especially important in patients with residual patent false lumen following surgery for acute type A aortic dissection.

Cardiac surgery in patients aged 80 years and older

OBJECTIVEnWe studied disease and surgical outcomes in an 80-plus age group to determine the feasibility of cardiac surgery at this age.nnnMETHODSnBetween January 1991 and August 2000, we statistically analyzed 19 variables in 62 consecutive cases of cardiac surgery in the 80-plus age group to predict in-hospital and long-term mortality. Cases were classified by disease type (ischemic heart disease (IHD), n = 39; valvular heart disease (VHD) n = 19; and mechanical complications associated with acute myocardial infarction, n = 4; and by surgical status (emergency, n = 6; urgent, n = 10; and elective, n = 46). We compared these with 370 patients 70 to 79 years undergoing similar procedures during the same interval.nnnRESULTSnNo significant difference was seen between groups in total in-hospital mortality--9.7% vs. 3.8%--or in-hospital mortality for IHD--2.6% vs. 4.2%--or VHD--10.5% vs. 2.8%. We found cardiopulmonary bypass time > 150 min. and dialysis to be independent risk factors for hospital death. Actuarial survival at 7.5 years overall was 39% in the 80-plus age group vs. 53% in the 70-79 age group for VHD and 38% in the 80-plus age group vs. 62% in the 70-79 age group. No significant difference was seen in survival between groups for IHD. Stroke proved to be an independent prognostic factor.nnnCONCLUSIONSnCardiac surgery is conducted feasibly in selected octogenarians, providing acceptable mortality and results similar to those achieved in those 70 to 79 years old.

A new cardiopulmonary bypass operating system permitting regulation by the surgeon in the operation field

For safer and easier management of the cardiop-ulmonary bypass (CPB) system, we have developed a new CPB operating system with which a surgeon in the operation field can also control CPB flow by manipulating venous line. With the insertion of a pressure-sensitive flow pump regulator into the conventional closed-circuit CPB system, a surgeon in the operation field can precisely control CPB flow by clamping a venous line to various degrees. In this regulator, two pressure sensors are attached both in front of and behind the flow control roller pump, which allows regulation of bypass flow in case of inadvertent total clamping of an arterial line. Additionally, by attaching a level sensed on-off switch of a volume control pump to a blood reservoir chamber, semiautomated regulation of blood reservoir volume is feasible. A clinical trial of five cases with this system revealed that our control system provided safe and effective flow control in both the initiating and the discontinuing phases of CPB with the surgeons manipulation. Moreover, throughout CBP, the blood reservoir volume was easily controlled only by changing the position of the level sensor, which reduced the perfusionists task of operating the volume and suction control roller pump. In conclusion, our system can provide not only a fail-safe system against abrupt kinking of the bloodstream line, but also reduction of the perfusionists burden during CPB management.