Satoru Wakasa

Assessment of hepatosplanchnic pathophysiology during thoracoabdominal aortic aneurysm repair using visceral perfusion and shunt

OBJECTIVE Despite the recognition of importance to avoid visceral ischemia during thoracoabdominal aortic aneurysm (TAAA) repair, the methodology of visceral perfusion seems still controversial and its pathophysiology has not been clearly understood. We investigated hepatosplanchnic metabolism during visceral perfusion/shunt in TAAA repair. METHODS Seventeen patients (10 male, 64+/-15 years old) who underwent elective TAAA repair using visceral perfusion/shunt under mild hypothermic distal aortic perfusion were retrospectively enrolled. Their aneurysm extension was type I and II in eight patients. In seven patients, four visceral arteries were perfused through a side-arm of distal aortic perfusion, while they were perfused by an independent pump in another five patients. In four of these 12 (two in each technique), visceral perfusion was converted into selective shunt after completion of aortic anastomosis. In the remaining five patients, four branches were initially perfused through a side-arm of distal aortic perfusion, and aortic perfusion was subsequently stopped after completion of aortic anastomosis. Hepatic venous oxygen saturation (ShO(2)), oxygen and lactate extraction ratio (OER, LER), and arterial ketone body ratio (AKBR) were measured at six time points. RESULTS There was no mortality, liver/renal dysfunction, or spinal cord injury. Two patients required re-exploration for bleeding. Fourteen patients were extubated within 24h postoperatively. Mean intensive care unit stay was 2.3+/-1.7 days. During visceral perfusion, OER raised (31+/-13% to 68+/-21%, p=0.0012) and ShO(2) decreased (67+/-12% to 34+/-24%, p=0.0026) significantly. They recovered to baseline at skin closure. During the same period, LER (41+/-22% to -1+/-34%, p=0.0035) and AKBR (0.47+/-0.13 to 0.20+/-0.08, p=0.0012) significantly decreased. AKBR recovered to baseline at skin closure, but LER did not. ShO(2) (R(2)=0.483, p=0.0257) and LER (R(2)=0.774, p=0.0018) at skin closure and LER after initiation of partial cardiopulmonary bypass (R(2)=0.427, p=0.0211) had significant correlation with postoperative peak serum bilirubin level. AKBR after initiation of partial cardiopulmonary bypass had significant correlation with postoperative peak serum alanine aminotransferase level (R(2)=0.289, p=0.0476). CONCLUSIONS Visceral perfusion/shunt in TAAA repair may avoid critical irreversible hepatosplanchnic ischemia but provide unphysiological blood flow to the liver and thus should be shortened.

Risk scores for predicting mortality after surgical ventricular reconstruction for ischemic cardiomyopathy: Results of a Japanese multicenter study

OBJECTIVES Surgical ventricular reconstruction has been believed to be beneficial for those with ischemic cardiomyopathy. However, the effectiveness of surgical ventricular reconstruction was not proved by a large-scale trial, and no report has clearly demonstrated the exact indications and limitations of surgical ventricular reconstruction. The purpose of this study was to elucidate predictive factors of mortality after surgical ventricular reconstruction and to develop a prognostic model by calculating risk scores. METHODS The study subjects were 596 patients who underwent surgical ventricular reconstruction for chronic ischemic heart failure in 11 Japanese cardiovascular hospitals between 2000 and 2010. Potential predictors of postoperative mortality were assessed using the Cox proportional hazards model, and a risk score was calculated. RESULTS Forty-one patients died before discharge, and 81 patients died during a mean follow-up time of 2.9 years. Four independent predictors of mortality were identified: age, Interagency Registry for Mechanically Assisted Circulatory Support profile, left ventricular ejection fraction, and severity of mitral regurgitation. Each variable was assigned a number of points proportional to its regression coefficient. A risk score was calculated using the point scores for each patient, and 3 risk groups were developed: a low-risk group (0-4 points), an intermediate-risk group (5-6 points), and a high-risk group (7-12 points). Their 3-year survivals were 93%, 81%, and 44%, respectively (log-rank P < .001). Harrells C-index of the predictive model was 0.69. CONCLUSIONS A simple prognostic model was developed to predict mortality after surgical ventricular reconstruction. It can be useful in clinical practice to select treatment options for ischemic heart failure.

Surgical Strategy for Ischemic Mitral Regurgitation Adopting Subvalvular and Ventricular Procedures

PURPOSE The progression of left ventricular (LV) remodeling and subsequent mitral valve tethering impair the results of reduction annuloplasty for ischemic mitral regurgitation (MR). METHODS We studied 90 patients who underwent surgical repair of ischemic MR between 1999 and 2013 according to our surgical strategy adding submitral and ventricular procedures to annuloplasty as follows: annuloplasty alone (stage 1, n = 30), additional papillary muscle approximation (PMA) for progression of tethering (stage 2, n = 26), and additional left ventriculoplasty with PMA for progression of LV remodeling and tethering (stage 3, n = 34). RESULTS The preoperative New York Heart Association (NYHA) functional classes (2.5 ± 0.7, 3.1 ± 0.7 and 3.3 ± 0.7 for stages 1, 2 and 3, respectively, P <0.001), LV end-diastolic diameters (56 ± 7 mm, 66 ± 5 mm and 70 ± 7 mm, P <0.001), and LV ejection fractions (45 ± 12%, 32 ± 9% and 27 ± 9%, P <0.001) significantly differed among the stages. In contrast, the MR grades did not significantly differ (2.9 ± 0.8, 3.0 ± 1.0, and 2.9 ± 1.1, respectively; P = 0.93). Both the rates of cardiac-related survival and freedom from reoperation were comparable among the 3 groups (log-rank P = 0.92 and 0.58, respectively). CONCLUSION Additional submitral and ventricular procedures can compensate for the possible impairment of the outcomes after annuloplasty alone for ischemic MR in patients with severe LV remodeling and tethering.

Slope in preload recruitable stroke work relationship predicts survival after left ventriculoplasty and mitral repair in patients with idiopathic cardiomyopathy

BACKGROUND Left ventriculoplasty (LVP) and mitral valve plasty (MVP) are sometimes effective for patients with idiopathic dilated cardiomyopathy (DCM) who are not eligible for heart transplantation. Strict patient selection is warranted for these controversial procedures. METHODS AND RESULTS The subjects were 18 patients with idiopathic DCM and mitral regurgitation who had not been indicated for heart transplantation due to either older age or patient refusal, and who underwent LVP and MVP. Their mean age was 57±14 years and 50% were dependent on catecholamine infusion. The preload recruitable stroke work (PRSW) relationship and its slope (Mw) were estimated by a single-beat technique using transthoracic echocardiography. There were one 30-day mortality and six (33%) hospital deaths due to heart failure. The one-year survival rate was 50%. Left ventricular end-diastolic dimension (LVDd) decreased from 77±11 to 68±11mm (p=0.001) whereas the ejection fraction did not change. Preoperative Mw was significantly higher in one-year survivors than that in non-survivors (54±17ergcm(-3)10(3) vs. 31±10ergcm(-3)10(3), p=0.005). Preoperative LVDd was not different between the groups. The cut-off value of 42ergcm(-3)10(3) for Mw predicted one-year survival with high sensitivity (100%) and specificity (77%). CONCLUSIONS Mw, the slope in the PRSW relationship, may predict survival after LVP and MVP in patients with idiopathic DCM.

A semiquantitative analysis of reactive astrogliosis demonstrates its correlation with the number of intact motor neurons after transient spinal cord ischemia

OBJECTIVE We evaluated the relationship between reactive astrogliosis and delayed motor neuron death after transient spinal cord ischemia in rabbits using a semiquantitative analysis of glial fibrillary acidic protein expression. METHODS Spinal cord ischemia was induced by means of balloon occlusion of the infrarenal aorta for 15 minutes at 39 degrees C in 18 New Zealand white rabbits. At 1, 3, and 7 days after reperfusion, 6 animals at each time point were killed, and the spinal cord was removed for histologic and immunohistochemical study. The variables analyzed were (1) neurologic function (Johnson score) at every 24 hours after reperfusion, (2) the number of intact motor neurons and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling-positive positive neurons, and (3) expression of glial fibrillary acidic protein in the gray and white matter, which was expressed as the percentage of stained area. RESULTS All animals presented delayed motor neuron death. The number of intact neurons decreased correlatively with neurologic function. No obvious terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling-positive cells were observed. Glial fibrillary acidic protein expression increased with time in both the gray and white matter, representing the development of reactive astrogliosis. Significant correlation was found between glial fibrillary acidic protein expression and the number of intact motor neurons on the third day in both the gray (r(2) = 0.726, P = .031) and white (r(2) = 0.927, P = .002) matter. CONCLUSIONS Reactive astrogliosis 3 days after transient spinal cord ischemia correlates with the number of intact motor neurons. Our method for semiquantitative analysis of reactive astrogliosis is simple and reproducible and seems useful for such experimental studies.

Impact of left ventricular remodelling on outcomes after left ventriculoplasty for ischaemic cardiomyopathy: Japanese surgical ventricular reconstruction group experience

OBJECTIVES Surgical ventricular reconstruction (SVR) for patients with severe left ventricular (LV) remodelling due to ischaemic cardiomyopathy is still controversial, because the Surgical Treatment for Ischaemic Heart Failure (STICH) trial demonstrated that SVR not only has no beneficial effect on survival compared with coronary artery bypass grafting (CABG) alone, but also is worse for those with a larger LV. Therefore, we assessed the impact of LV remodelling on the outcomes after SVR for ischaemic cardiomyopathy in Japan, using Di Donatos LV shape classification. METHODS From 2000 to 2010, 627 patients underwent SVR for ischaemic heart failure in 11 Japanese hospitals. To assess the patients with an LV ejection fraction (LVEF) of ≤ 35% like the STICH trial, considering the severity of LV remodelling, the patients with a preoperative LVEF of >35%, no preoperative LV volume assessment and no preoperative LV shape classification were excluded. Finally, 323 patients were selected as the study subjects. The LV shape was divided into three types according to Di Donatos classification. Types 1 and 3 indicate the aneurysmal and globally akinetic LV, respectively. Type 2 is the intermediate shape. RESULTS Type 1, 2 and 3 LV shapes were observed in 85 (26%), 104 (32%) and 134 (42%) of the patients, respectively. The preoperative LV volume and diameter increased if the LV became more akinetic (Type 3 > 2 > 1, P < 0.001). LVEF was lower in those with more akinetic LV (P = 0.002). The preoperative LV end-diastolic volume index and LVEF in Type 3 patients were 133 ± 47 ml/m(2) and 22 ± 7%, respectively. Mitral valve repair was more frequently performed for patients with the Type 3 LV shape (65%) than for the others (P < 0.001). The hospital mortality rates were 2.4, 2.9 and 7.4% for Type 1, 2 and 3 patients, respectively (P = 0.16). Kaplan-Meier analysis demonstrated no significant difference in mortality among the three groups (log-rank P = 0.37). The 5-year survival rates were 81, 70 and 73% for Type 1, 2 and 3 patients, respectively. CONCLUSIONS The severity of LV remodelling did not affect survival after SVR plus CABG. The results of SVR were acceptable even for those with globally akinetic LV due to ischaemic cardiomyopathy.

Effects of Surgical Ventricular Reconstruction and Mitral Complex Reconstruction on Cardiac Oxidative Metabolism and Efficiency in Nonischemic and Ischemic Dilated Cardiomyopathy

OBJECTIVES The aim of this study was to investigate the effects of surgical ventricular reconstruction (SVR) on cardiac efficiency as a surrogate marker for cardiac function and oxidative metabolism in patients with severe heart failure. BACKGROUND Our new integrated overlapping left ventriculoplasty, modified SVR, combined with mitral complex reconstruction, reduce left ventricular (LV) volume associated with improvement of symptoms of heart failure. METHODS Twelve consecutive patients with end-stage heart failure due to nonischemic dilated cardiomyopathy (DCM) (n = 6) and ischemic dilated cardiomyopathy (ICM) (n = 6) who underwent SVR were studied. Myocardial oxidative metabolism per gram of tissue was estimated by monoexponential clearance of (11)C-acetate positron emission tomography (K(mono)). Forward stroke volume at the LV outflow tract was measured by echocardiography. Cardiac efficiency was estimated by the ratio of external work (stroke volume at the LV outflow tract index × systolic blood pressure × heart rate) to K(mono) before and 1 month after SVR. RESULTS After SVR, medians of New York Heart Association functional class significantly improved from 3 to 1.5 (p < 0.01) in both DCM and ICM patients. End-systolic and end-diastolic volume and LV mass significantly decreased in both groups. Stroke volume at the LV outflow tract increased from 43 ± 8 ml to 52 ± 11 ml (p = 0.028) in DCM patients, but not in ICM patients (49 ± 21 ml to 59 ± 26 ml, p = 0.12). K(mono) × LV mass, as an index of global LV oxidative metabolism, decreased in DCM patients (13.6 ± 1.9 g/min vs. 8.6 ± 1.5 g/min, p = 0.03) and ICM patients (12.0 ± 3.4 g/min vs. 9.2 ± 1.0 g/min, p = 0.06). As a result, cardiac efficiency increased in all patients with DCM (3.34 ± 0.46 × 10E6 vs. 4.74 ± 0.88 × 10E6 mm Hg·ml·min/m(2), p = 0.03) and in 5 of 6 patients with ICM (4.54 ± 1.66 × 10E6 vs. 5.99 ± 2.11 × 10E6 mm Hg·ml·min/m(2), p = 0.12). CONCLUSIONS Combined surgery with SVR and mitral complex reconstruction reduced LV volume in association with improvement of cardiac efficiency in patients with severe heart failure.

Aortic Valve Replacement Through Left Thoracotomy After Esophageal Operation

A 67-year-old man was referred for aortic valve surgery due to aortic valve regurgitation. He underwent an aortic valve replacement through a left thoracotomy, since he had a history of esophageal surgery with substernal gastric tube reconstruction and lymph node dissection through a right thoracotomy 14 years ago. The aortic valve was successfully replaced with excellent visualization using vacuum-assisted venous drainage on a cardiopulmonary bypass. Although exposing the aortic valve through a left thoracotomy is difficult, the application of vacuum-assisted venous drainage helps visualize the aortic valve in this approach.

Left-ventricular electromechanical delay is prolonged in patients with postoperative atrial fibrillation

OBJECTIVE Although several risk factors for postoperative atrial fibrillation (AF) have been proposed, it remains the most common complication after cardiac surgery, even in low-risk patients. There is still no single reliable and reproducible parameter for predicting AF, and no standardized recommendation exists for this issue. Electromechanical delay (excitation-contraction coupling delay) is the time delay from the electrical activation to the actual systolic motion, and it reflects abnormality in calcium-handling proteins, which is considered one mechanism of postoperative AF. We hypothesized that left-ventricular electromechanical delay (LVEMD) is correlated to postoperative AF and serially examined it by echocardiography. METHODS We prospectively included 16 patients with relatively low risk for AF, who underwent cardiac surgery. The inclusion criteria were younger than 80 years, an ejection fraction greater than 45%, a left-atrial dimension less than 50mm, and a brain natriuretic peptide (BNP) value less than 250 pg ml⁻¹. Postoperative AF for 10 postoperative days was monitored by 24-h electrocardiogram. The LVEMD was assessed by pulse-wave tissue Doppler echocardiography before and 1, 3, and 7 days after the operation. Serum BNP, adrenalin, and noradrenalin levels were also examined at the same time. RESULTS Postoperative AF was detected in six (37.5%) patients. There was no significant difference in heart rate, QRS duration, and serum hormones between the non-AF (n = 10) and AF (n = 6) groups. Although the preoperative LVEMD was comparable, that on postoperative day 1 of the AF group was significantly longer than that of the non-AF group (in the septal wall, 174 ± 50 vs 101 ± 36 ms, p = 0.020; in the lateral wall, 195 ± 71 and 111 ± 37 ms, p = 0.029). A LVEMD on postoperative day 1 greater than 150 ms well predicted postoperative AF (sensitivity, 75% and 75%; specificity, 100% and 86%, in septal and lateral LVEMDs, respectively). CONCLUSIONS LVEMD is prolonged in patients with postoperative AF. This could be a new predicting parameter for AF in low-risk patients.

Surgery for Left Ventricular Outflow Tract Obstruction with a Relatively Thin Interventricular Septum

Abstract Background To examine the results of myectomy and mitral valve surgery for systolic anterior motion (SAM) of the mitral valve and left ventricular outflow tract obstruction (LVOTO) with a relatively thin interventricular septum. Methods The subjects were 12 patients with SAM and LVOTO. Eight had hypertrophic obstructive cardiomyopathy (HOCM) with a mean interventricular septal thickness of 16 mm. Three had sigmoid septum and one had an unknown etiology. For HOCM, isolated extended myectomy was performed when mitral regurgitation was mild (n = 1) and extended myectomy plus mitral valve surgery was performed when mitral regurgitation was more than mild (n = 4) or primary valve etiologies existed (n = 3). Myectomy was performed for the three cases with sigmoid septum. Myectomy plus height reduction of the posterior mitral leaflet was performed for the one case with the unknown etiology of SAM. Results In the patients with HOCM, the maximum LVOT pressure gradient significantly decreased from 140 ± 18 to 16 ± 6 and 3 ± 3 mm Hg, while mitral regurgitation significantly decreased from 2.3 ± 0.5 to 0.5 ± 0.3 and 0.4 ± 0.2 at pre‐op, early post‐op, and last follow‐up (3 ± 1 years), respectively. In the other etiologies, the maximum LVOT pressure gradient changed from 56 ± 15 to 25 ± 15 and 5 ± 4 mm Hg; mitral regurgitation changed from 2.0 ± 0.6 to 1.3 ± 0.3 and 1.3 ± 0.8, at pre‐op, early post‐op, and the last follow‐up (3 ± 2 years), respectively. Conclusion Myectomy with mitral valve surgery is an option for SAM and LVOTO in patients with a relatively thin interventricular septum.