Eiki Tayama

Obstruction of st jude medical valves in the aortic position: histology and immunohistochemistry of pannus

OBJECTIVE This study aims to reveal the morphological, histological, and immunohistochemical mechanism of pannus formation using resected pannus tissue from patients with prosthetic valve dysfunction. METHOD Eleven patients with prosthetic valve (St Jude Medical valve) dysfunction in the aortic position who underwent reoperation were studied. We used specimens of resected pannus for histological staining (hematoxylin and eosin, Grocotts, azan, elastica van Gieson) and immunohistochemical staining (transforming growth factor-beta, transforming growth factor-beta receptor 1, alpha-smooth muscle actin, desmin, epithelial membrane antigen, CD34, factor VIII, CD68KP1, matrix metalloproteinase-1, matrix metalloproteinase-3, and matrix metalloproteinase-9). RESULTS Pannus without thrombus was observed at the periannulus of the left ventricular septal side; it extended into the pivot guard, interfering with the movement of the straight edge of the leaflet. The histological staining demonstrated that the specimens were mainly constituted with collagen and elastic fibrous tissue accompanied by endothelial cells, chronic inflammatory cells infiltration, and myofibroblasts. The immunohistochemical findings showed significant expression of transforming growth factor-beta, transforming growth factor-beta receptor 1, CD34, and factor VIII in the endothelial cells of the lumen layer; strong transforming growth factor-beta receptor 1, alpha-smooth muscle actin, desmin, and epithelial membrane antigen in the myofibroblasts of the media layer; and transforming growth factor-beta, transforming growth factor-beta receptor 1, and CD68KP1 in macrophages of the stump lesion. CONCLUSIONS Pannus appeared to originate in the neointima in the periannulus of the left ventricular septum. The structure of the pannus consisted of myofibroblasts and an extracellular matrix such as collagen fiber. The pannus formation after prosthetic valve replacement may be associated with a process of periannular tissue healing via the expression of transforming growth factor-beta.

Usefulness of a multidetector-row computed tomography scanner for detecting pannus formation

BACKGROUND Prosthetic valve dysfunction (PVD) as a result of pannus or thrombus formation is an infrequent but serious complication. Currently available diagnostic tools, however, are insufficient to detect a minute pannus and thrombi. The use of a more advanced diagnostic image, multidetector-row computed tomography scanner, may enable us to determine the anatomic and functional causes of PVD. METHODS Patients who underwent aortic valve replacement with a St. Jude Medical valve were examined by transthoracic echocardiography and cineradiography to diagnose PVD. Sixteen patients with PVD (PVD group) and 12 patients with normal prosthetic valve function (control group) were studied using the multidetector-row computed tomography scanner. The multidetector-row computed tomography findings in 2 patients with PVD were validated by the observations during reoperation. RESULTS In 13 of 16 patients (81%) in the PVD group and 3 of 12 patients (25%) in the control group, multidetector-row computed tomography demonstrated that an abnormal small tissue, regarded as pannus, was found to extend from the left ventricular septum into the pivot guard. These findings were confirmed by the observations during reoperation in 2 patients in the PVD group. CONCLUSIONS Multidetector-row computed tomography can be a useful diagnostic technique for anatomic and functional evaluation of PVD as a result of pannus formation.

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.

Tricuspid valve replacement with the St. Jude Medical valve: 19 years of experience

OBJECTIVE The choice of the valve substitute in the tricuspid position remains controversial. A St. Jude Medical valve is a choice of valve substitute and its lower thrombogenicity and excellent hemodynamic performance have been reported even in the tricuspid position. However, little is known of the long-term durability of the St. Jude Medical valve in the tricuspid position. Our long-term experience of tricuspid valve replacement showed the higher thrombogenicity than we had expected, therefore, this study was done to reconsider our strategy for valve choice. METHODS This study reviewed 23 patient who underwent 25 tricuspid valve replacements with the St. Jude Medical valves from 1980 to 1997. The mean age was 40 years. Eleven patients (48%) were men. There were four in-hospital deaths (17%). The remaining 19 patients were all alive and followed from 2.2 to 19.0 years (mean 11.8 years). RESULTS The overall survival, including hospital mortality, was 83%, 10 and 15 years after surgery. Valve thrombosis occurred in six patients. Freedom from valve thrombosis was 78 and 70%, 10 and 15 years after surgery, respectively. The linearized rate of the valve thrombosis was 2.9%/patient-years. Six patients required reoperation. The mean interval to reoperation was 9.5 years. Freedom from reoperation was 83% and 75%, 10 and 15 years after surgery, respectively. The linearized rate of the reoperation was 2.8%/patient-years. No structural valve deterioration was found. Echocardiographic study showed that the function of the St. Jude Medical valve without valve-related complications was well maintained. CONCLUSIONS The higher thrombogenicity of the St. Jude Medical valve in the tricuspid position altered our choice of valve substitutes from the St. Jude Medical valve to a bioprosthesis which is lack of need for anticoagulant therapy except for juvenile patients who are able to maintain potent anticoagulant therapy.

Obstruction of St Jude Medical Valves in the Aortic Position: A Consideration for Pathogenic Mechanism of Prosthetic Valve Obstruction:

Between 1995 and 2000, 8 patients with St. Jude Medical (SJM) valves in the aortic position required 9 redo valve replacement for prosthetic valve obstruction. Obstruction of the prosthetic valve was diagnosed by simultaneous echocardiography and cineradiography, and process of restricted leaflet movement that progressed to hemodynamic impairment was observed by serial studies in three recent patients. An oral anticoagulation was considered to be adequate in all patients except one patient who had withdrawal of warfrain. Pannus was the sole cause of valve obstruction in seven events in 6 patients, and both thrombus and pannus in 2 patients. Pannus overgrowth was found on the inflow aspect of the SJM valve, and involved the ends of the straight edge of the leaflets over pivot guards. These results suggest that pannus might play the primary role in development of obstruction of aortic SJM valves in patients on adequate oral anticoagulation.

Effects of intraoperative administration of atrial natriuretic peptide

BACKGROUND Biological activity of endogenous atrial natriuretic peptide (ANP) may decrease during cardiopulmonary bypass. To evaluate the effects of intraoperative administration of exogenous ANP in patients undergoing cardiopulmonary bypass, we conducted a prospective randomized study. METHODS Eighteen patients undergoing mitral valve surgery were randomized to receive either ANP treatment (ANP group; n = 9) or no ANP treatment (control group; n = 9). Atrial natriuretic peptide was given immediately after initiation of cardiopulmonary bypass for 6 hours (0.05 microg x kg(-1) x min(-1)). Plasma ANP, brain natriuretic peptide and cyclic guanosine monophosphate (cGMP) levels, hemodynamic variables and renal function were assessed perioperatively. RESULTS Administration of ANP increased plasma cyclic guanosine monophosphate levels, urine output and fractional sodium excretion, and decreased preload, afterload and plasma brain natriuretic peptide levels significantly (p < 0.05). Plasma cyclic guanosine monophosphate levels correlated with plasma ANP levels (r = 0.95, p = 0.0001), correlated with fractional sodium excretion (r = 0.53, p = 0.02), and correlated inversely with systemic vascular resistance (r = -0.54, p = 0.02). CONCLUSIONS Intraoperative administration of ANP had potent effects on natriuresis and systemic vasodilation by elevating cyclic guanosine monophosphate levels. The results suggest that the technique is useful for the management of hemodynamics and water-sodium retention after cardiopulmonary bypass.

Long-term results of aortic valve replacement with a small St. Jude medical valve in Japanese patients.

BACKGROUND The use of small aortic valve prostheses is still controversial because of negative effects caused by residual obstruction of the left ventricular outflow tract. This study evaluated the long-term results after aortic valve replacement with a small valve from St. Jude Medical (St. Paul, MN). METHODS Between 1980 and 1999, 221 patients underwent isolated aortic valve replacement with a 23-mm or smaller St. Jude Medical valve. The mortality rate and complications were analyzed, echocardiography was performed, and peak pressure gradient, mean pressure gradient, indexed effective orifice area, and left ventricular mass index were measured. RESULTS The follow-up rate in the 221 patients was 99.5% (maximum length, 24.1 years; mean, 10.3 years). Patients with a 19-mm valve were mainly women, older, and had smaller body surface areas. Freedom from valve-related death at 20 years was 100%, 86.0%, and 90.2% in patients with 19-, 21-, and 23-mm valves, respectively. There were no significant differences in the actuarial freedom from valve-related deaths. Echocardiography showed significantly higher peak (32.3 mm Hg) and mean pressure gradients (17.6 mm Hg) and a smaller indexed effective orifice area (0.70 +/- 0.15 cm(2)/m(2)) in patients with a 19-mm valve than in those with a 21- or 23-mm valve. Moderate prosthesis-patient mismatch was present in most patients with a 19-mm valve according to one definition; however, the improvements in ejection fraction and left ventricular mass index were significant, and functional recovery (mean New York Heart Association class, 1.3 +/- 0.5; mean specific activity scale, 5.1 +/- 0.8 metabolic equivalents) was satisfactory. CONCLUSIONS The present long-term results demonstrate that a small St. Jude Medical valve can be advantageously used in most Japanese patients because their body size is generally smaller than that of Western patients. These findings also emphasize that it is not prosthesis size per se that matters but rather the relation between body size and prosthesis size.

Initial experience with the Nikkiso centrifugal pump during thoracoabdominal aortic aneurysm repair

PURPOSE Several centers use atriodistal bypass (ADB) as a protective adjunct against distal ischemia during extensive thoracoabdominal aortic aneurysm (TAAA) repair. Most current ADB circuits use indirect-drive centrifugal pumps. The purpose of this report is to describe our initial clinical experience with the Nikkiso pump, a more compact direct-drive centrifugal pump recently developed at Baylor, for ADB during TAAA repair. METHODS The Nikkiso pump was used for ADB perfusion in 10 consecutive patients during graft repair of TAAAs (six Crawford extent I and four extent II). Two patients had aortic dissection. In the four patients who had extent II repairs, selective renal and visceral perfusion was also performed with the Nikkiso pump. RESULTS No mechanical pump malfunctions or adverse events related to the device occurred. All 10 patients survived and were discharged from the hospital. No patient had paraplegia after surgery. Two patients had delayed lower extremity weakness after undergoing extent I repairs; both recovered and were ambulating at the time of discharge. No complications were associated with bleeding or cerebral, respiratory, renal, or hepatic function. CONCLUSIONS Our initial experience with the Nikkiso centrifugal pump during TAAA repair demonstrated excellent pump function that provided sufficient flow for both distal aortic and selective organ perfusion. The prevention of permanent spinal cord injury and distal organ failure was successful in this group.

Effect of Surgery for Atrial Fibrillation Associated With Mitral Valve Disease

BACKGROUND The purpose of this study is to evaluate the effect of surgery for atrial fibrillation (AF) associated with mitral valve disease. METHODS From September 1994 to December 2006, 244 patients who underwent mitral valve surgery were enrolled in this study. The maze procedure or pulmonary vein isolation was concomitantly performed in 147 patients, while the remaining 97 patients were not surgically treated for AF. The patients were divided into 3 groups based on their cardiac rhythm at discharge from the hospital: the sinus group (108 patients), the intractable AF group (39 patients), and the untreated AF group (97 patients). The clinical features and late results of patients were compared among these groups. RESULTS Early mortality rate was 0.7% and no major morbid events had occurred. Follow-up was completed in 95.6% of the patients and the mean follow-up period was 6.03 years. Actuarial survival was not significant between the sinus and AF groups. Actuarial freedom from thromboembolism at 5 and 10 years was 96.5% in the sinus group, 82.4% and 78.1%, respectively, in the intractable AF group, and 93.4% and 89.1%, respectively, in the untreated AF group; statistical significance was observed among the 3 groups (p = 0.01). By means of multivariate analysis, intractable AF was found to be the only risk factor for thromboembolism and other complications. CONCLUSIONS Atrial fibrillation associated with mitral valve disease should be treated, because restoration of the sinus rhythm might lead to a lower incidence of thromboembolism and valve-related complications in the later period.

Antiinflammatory effects of colforsin daropate hydrochloride, a novel water-soluble forskolin derivative

BACKGROUND To evaluate the effects of colforsin daropate hydrochloride (colforsin), a water-soluble forskolin derivative, on hemodynamics and systemic inflammatory response after cardiopulmonary bypass, we conducted a prospective randomized study. METHODS Twenty-nine patients undergoing coronary artery bypass grafting were randomized to receive either colforsin treatment (colforsin; n = 14) or no colforsin treatment (control; n = 15). Administration of colforsin (0.5 microg.kg(-1).min(-1)) was started after induction of anesthesia and was continued for 6 hours. Perioperative cytokine and cyclic adenosine monophosphate levels, hemodynamics, and respiratory function were measured serially. RESULTS Marked positive inotropic and vasodilatory effects were observed in patients receiving colforsin. Interleukin 1beta, interleukin 6, and interleukin 8 levels after cardiopulmonary bypass were significantly (p < 0.05) lower in the colforsin group. Plasma levels of cyclic adenosine monophosphate increased significantly (p < 0.05) in the colforsin group, and the levels correlated inversely (r = -0.56, p = 0.002) with the respiratory index after cardiopulmonary bypass. CONCLUSIONS Intraoperative administration of colforsin daropate hydrochloride had potent inotropic and vasodilatory activity and attenuated cytokine production and respiratory dysfunction after cardiopulmonary bypass. The results indicate that the technique can be a novel therapeutic strategy for the systemic inflammatory response associated with cardiopulmonary bypass.