Chronic expanding intrapericardial hematoma after coronary artery bypass surgery presenting with congestive heart failure

We report the successful treatment of a rare case of chronic expanding intrapericardial hematoma that had slowly developed into a large mass after coronary artery bypass surgery. An 85-year-old man with a history of coronary artery bypass surgery presented with dyspnea on exertion and leg edema in 2006. Chest roentgenograph demonstrated right pleural effusion and severe pulmonary edema. An echocardiographic study demonstrated a mass located posterior to the left ventricle that severely compressed the left ventricle toward the ventricular septum. Surgical resection of the mass was planned to release the symptoms and to confirm the diagnosis of the mass. The mass was completely resected through a left thoracotomy, and the histological findings confirmed the diagnosis of a chronic expanding intrapericardial hematoma. The patient's postoperative course was uneventful, and his symptoms improved markedly. There has been no sign of recurrence 1 year after the operation.

Severely calcified constrictive pericarditis simulating a mediastinal tumor and obstructing the right ventricular inflow tract

We report a rare case of constrictive pericarditis that stimulated a large mediastinal tumor obstructing the right ventricular inflow tract. A 58-year-old woman was referred to our hospital because of a recent increase of dyspnea and facial edema. Computed tomography revealed severely thickened calcification, including a low-density area, presenting as a mediastinal tumor, compressing the right ventricular inflow tract. A complete resection was performed, and her symptoms dramatically improved. Idiopathic constrictive pericarditis was diagnosed pathologically.

Simple and Uniform Technique for Combined Repair of Aortic Arch and Root Replacement

We present herein a simple and uniform repair technique for combined aortic arch and root aneurysms. Our method is performed under an open distal procedure and includes selective antegrade cerebral perfusion, adequate myocardial preservation, a four-branched composite valve graft, and a long elephant trunk anastomosis proximal to the innominate artery. The technique was designed to reduce morbidity and mortality associated with aortic arch and root replacements, as well as allow for easier performance of subsequent downstream operations.

[Intermediate results of aortic valve replacement using 19 mm bioprosthetic valve]

Pre- and postoperative hemodynamic parameters and activity of daily life were reviewed to estimate the effectiveness of the valve in 12 cases of single aortic valve replacement (AVR) using 19 mm bioprosthesis. All implanted prostheses were stented-valves. Carpentier-Edwards pericardial valve was used in 7 cases and Mosaic valve in 5. Left ventricular mass index (LVMI) significantly decreased from 167 +/- 36 to 133 +/- 27 g/m2 in the early postoperative period, and to 115 +/- 24 g/m2 in the intermediate phase. However, postoperative LVMI remained higher in patients with body surface area (BSA) over 1.5 m2 than in those under 1.5 m2. Postoperative activity indicated by New York Heart Association (NYHA) grade significantly improved from 2.3 +/- 1.1 to 1.4 +/- 0.5. These results indicates usefulness of 19 mm bioprosthetic valve for reducing left ventricular hypertrophy and improving activity, especially in patients with BSA smaller than 1.5 m2.

Precise Quantification of Pulsatility is a Necessity for Direct Comparisons of Six Different Pediatric Heart-Lung Machines in a Neonatal CPB Model

Generation of pulsatile flow depends on an energy gradient. Surplus hemodynamic energy (SHE) is the extra hemodynamic energy generated by a pulsatile device when the adequate pulsatility is achieved. The objective of this study was to precisely quantify and compare pressure-flow waveforms in terms of surplus hemodynamic energy levels of six different pediatric heart-lung machines in a neonatal piglet model during cardiopulmonary bypass (CPB) procedures with deep hypothermic circulatory arrest (DHCA). Thirty-nine piglets (average weight, 3 kg) were subjected to CPB with a hydraulically driven physiologic pulsatile pump (PPP; n=7), Jostra-HL 20 pulsatile roller pump (Jostra-PR; n=6), Stockert Sill pulsatile roller pump (SIII-PR; n=6), Stockert Sill mast-mounted pulsatile roller pump with a miniature roller head (Mast-PR; n=7), Stockert Sill mast-mounted nonpulsatile roller pump (Mast-NP; n=7), or Stockert CAPS nonpulsatile roller pump (CAPS-NP, n=7). Once CPB was begun, each animal underwent 20 minutes of hypothermia, 60 minutes of DHCA, 10 minutes of cold reperfusion, and 40 minutes of rewarming. The pump flow rate was maintained at 150 ml x kg(-1) x min(-1) and the mean arterial pressure (MAP) at 45 mm Hg. In the pulsatile experiments, the pump rate was kept at 150 bpm and the stroke volume at 1 ml/kg. The SHE (ergs/cm3) = 1,332 ([(integral fpdt) / (integral fdt)] - MAP) was calculated at each experimental stage. During normothermic CPB (15 minutes on pump), the physiologic pulsatile pump generated the highest surplus hemodynamic energy (8563 +/- 1918 ergs/cm3, p < 0.001) compared with all other pumps. The Jostra HL-20 and Stockert Sill pulsatile roller pumps also produced adequate surplus hemodynamic energy. Nonpulsatile roller pumps and the Stockert Sill mast-mounted pulsatile roller pump did not generate any extra hemodynamic energy. During hypothermic CPB and after DHCA and rewarming, the results were extremely similar to those seen during normothermic CPB. The surplus hemodynamic energy formula is a novel method to precisely quantify different levels of pulsatility and nonpulsatility for direct and meaningful comparisons. The PPP produced the greatest surplus hemodynamic energy. Most of the pediatric pulsatile pumps (except Mast-PR) generated significant surplus hemodynamic energy. None of the nonpulsatile roller pumps generated adequate surplus hemodynamic energy.

Evaluation of the Mitral Valve Leaflet Morphology After Mitral Valve Reconstruction with a Concept "Coaptation Length Index"

BACKGROUND

In clinical settings, information on morphology of mitral valve leaflet after mitral valve reconstruction is limited.

METHODS

Between January 1996 and June 2000, 36 patients underwent mitral valve repair for mitral regurgitation (MR). The etiology of mitral insufficiency was prolapse, dilated annulus, and ischemia. Ring annuloplasty was performed in all cases. Mitral valve short-axis dimension (MVd), vertical distance between annular line and closing point (Vd), coaptation length (CL), and coaptation length index (CLI) were measured by two-dimensional transesophageal echocardiography for the present 11 cases.

RESULTS

In 11 cases, residual MR, using a scale from 0 to 4, was 0 in 5 patients, 1 in 4 patients, 2 in 2 patients whose etiology of regurgitation was cardiomyopathy. MVd and Vd decreased significantly (38.7+/- 6.2 to 27.0 +/- 5.6 mm, 10.1 +/- 7.7 to 6.5 +/- 4.6 mm, respectively). CL and CLI increased significantly (6.4 +/- 2.4 to 11.6 +/- 4.6 mm, 0.16 +/- 0.06 to 0.44 +/- 0.21, respectively). Among those indices, only CLI has a statistically significant negative correlation with the degree of residual MR.

CONCLUSION

Mitral valve ring annuloplasty produces the morphologic change of the mitral apparatus, especially increase of CLI, which may be one of the main factors in regulation of regurgitation.

[Perioperative multivessel coronary vasospasm as a cause of cardiogenic shock immediately after off-pump coronary artery bypass grafting surgery: a case report]

Perioperative coronary vasospasm has been recognized as a possible cause of myocardial infarction or low output syndrome after open heart operations. A 57-year-old male suffered cardiogenic shock immediately after off-pump coronary artery bypass grafting surgery. Emergent angiography performed under intraaortic balloon pumping and percutaneous cardiopulmonary support revealed severe multivessel coronary vasospasm which was effectively treated with a high dose intracoronary administration of isosorbide dinitrate. Emergent angiography for patients with cardiogenic shock after open heart operation is feasible and effective for the diagnosis and treatment of perioperative coronary vasospasm.

Evaluation of the Mitral Valve Leaflet Morphology after Mitral Valve Reconstruction with a Concept "Coaptation Length Index"

BACKGROUND

In clinical settings, information on morphology of mitral valve leaflet after mitral valve reconstruction is limited.

METHODS

Between January 1996 and June 2000, 36 underwent mitral valve repair for mitral regurgitation (MR). The etiology of mitral insufficiency was prolapse, dilated annulus, and ischemic. Ring annuloplasty was performed in all cases. Mitral valve short-axis dimension (MVd), vertical distance between annular line and closing point (Vd), coaptation length (CL), coaptation length index (CL/MVd) were measured by the two-dimensional transesophageal echocardiography for the present 11 cases.

RESULTS

In 11 cases, residual MR, using a scale from 0 to 4, was 0 in 5 patients, 1 in 4 patients, 2 in 2 patients whose etiology of regurgitation was cardiomyopathy. MVd and Vd decreased significantly (38.7 +/- 6.2 to 27.0 +/- 5.6 mm, 10.1 +/- 7.7 to 6.5 +/- 4.6 mm, respectively). CL and CLI increased significantly (6.4 +/- 2.4 to 11.6 +/- 4.6 mm, 0.16 +/- 0.06 to 0.44 +/- 0.21, respectively). Among those index, only CLI have a statistically significant negative correlation with the degree of residual MR.

CONCLUSION

The mitral valve ring annuloplasty produce the morphologic change of mitral apparatus, especially the increase of CLI, which may be one of the main factors in regulation of regurgitation.

Mycotic aneurysm of the infrarenal abdominal aorta infected by Clostridium septicum: A case report of surgical management and review of the literature

We report a surgical case of mycotic aneurysm of the infrarenal abdominal aorta infected by Clostridium septicum. The patient was first treated with an in situ prosthetic graft replacement. When the infection recurred 5 weeks after the aortic surgery, the patient was successfully treated by transposition of rectus abdominis muscle flap around the graft. Only 19 cases of mycotic aneurysm or aortic dissection caused by Clostridium septicum have been reported. Ten of 12 patients who underwent vascular surgery survived, whereas all 7 patients who did not undergo surgery died. Surgical treatment should be undertaken since the surgical results seem satisfactory.

Usefulness of continuous air tonometry for evaluation of splanchnic perfusion during cardiopulmonary bypass

Although gastric mucosal tonometry has been reported as a useful method to assess splanchnic perfusion during cardiovascular surgery, the conventional discontinuous method of tonometry (saline tonometry) was cumbersome and prone to systematic errors. A new automated system of air tonometry (Tonocap; Datex Ohmeda, Helsinki, Finland) allows for frequent (every 10 minutes) measurement of gastric regional CO2 (PrCO2) and may be more suitable as a monitoring system in cardiac patients. We evaluated the usefulness of continuous air tonometry as a marker of splanchnic perfusion during cardiopulmonary bypass (CPB). In 19 patients (53-79 years, mean 63 years) who underwent cardiovascular surgery under standard CPB with mild hypothermia (32 degrees C) from January 2001 to May 2002, the PrCO2 and calculated intramucosal pH (pHi) of gastric tonometry was monitored using Tonocap, and their relation to postoperative visceral organ function was evaluated. The pHi significantly increased after initiation of CPB from 7.32 +/- 0.07 to 7.43 +/- 0.10 (p < 0.05) and then consistently decreased in all patients to 7.39 +/- 0.09 at the end of CPB. The value of PrCO2 significantly (p < 0.01) correlated with the value of pHi. The lowest value of pHi during CPB was significantly related to blood urea nitrogen (r = -0.75, p < 0.05), serum creatinine (r = -0.78, p < 0.05), creatinine clearance (r = 0.68, p < 0.05) on postoperative day 1, and blood urea nitrogen (r = -0.84, p < 0.01) on day 3. In contrast, arterial blood lactate level, venous oxygen saturation, and routinely measured hemodynamics (e.g., pump flow, arterial pressure) during CPB were unrelated to the postoperative visceral organ function. These results suggest that continuous monitoring of gastric regional CO2 and pHi by air tonometry system is useful for the evaluation of splanchnic perfusion during CPB and may contribute to improve CPB technique by allowing the early detection of visceral malperfusion.

Pediatric physiologic pulsatile pump enhances cerebral and renal blood flow during and after cardiopulmonary bypass

Controversy over benefits of pulsatile flow after pediatric cardiopulmonary bypass (CPB) continues. Our study objectives were to first, quantify pressure and flow waveforms in terms of hemodynamic energy, using the energy equivalent (EEP) formula, for direct comparisons, and second, investigate effects of pulsatile versus nonpulsatile flow on cerebral and renal blood flow, and cerebral vascular resistance during and after CPB with deep hypothermic circulatory arrest (DHCA) in a neonatal piglet model. Fourteen piglets underwent perfusion with either an hydraulically driven dual-chamber physiologic pulsatile pump (P, n = 7) or a conventional nonpulsatile roller pump (NP, n = 7). The radiolabeled microsphere technique was used to determine the cerebral and renal blood flow. P produced higher hemodynamic energy (from mean arterial pressure to EEP) compared to NP during normothermic CPB (13 +/- 3% versus 1 +/- 1%, p < 0.0001), hypothermic CPB (15 +/- 4% versus 1 +/- 1%, p < 0.0001) and after rewarming (16 +/- 5% versus 1 +/- 1%, p < 0.0001). Global cerebral blood flow was higher for P compared to NP during CPB (104 +/- 12 ml/100g/min versus 70 +/- 8 ml/100g/min, p < 0.05). In the right and left hemispheres, cerebellum, basal ganglia, and brainstem, blood flow resembled the global cerebral blood flow. Cerebral vascular resistance was lower (p < 0.007) and renal blood flow was improved fourfold (p < 0.05) for P versus NP, after CPB. Pulsatile flow generates higher hemodynamic energy, enhancing cerebral and renal blood flow during and after CPB with DHCA in this model.

An alternative approach using long elephant trunk for extensive aortic aneurysm: elephant trunk anastomosis at the base of the innominate artery

BACKGROUND

Although a staged elephant trunk procedure has been widely used, the early mortality of the first stage operation as well as the interval mortality between operations remains unsatisfactory. We developed an alternative elephant trunk procedure to reduce mortality and morbidity.

METHODS AND RESULTS

Ascending aorta and arch vessels were minimally dissected. During systemic cooling, a four-branched arch graft with a sewing "collar" and a long "elephant trunk" was prepared. The ascending aorta was opened under selective brain perfusion with moderate hypothermia (25 degrees C), and the elephant trunk was then pulled down into the descending aorta using the catching catheter introduced via a femoral artery. The elephant trunk anastomosis using the collar was made at the base of the innominate artery. The arch vessels were divided and closed at aortic stump, and grafted separately as a consequence of the very proximal site for the elephant trunk anastomosis. Between October 1998 and September 2001, 17 patients, ranging in age from 25 to 79 years (mean 67 years) with extensive aortic aneurysm underwent this operation. Preoperative cardiac complications included coronary artery disease in 5, aortic regurgitation in 3, and 3 of these 8 patients had poor left ventricular function with an ejection fraction less than 40%. Nine patients underwent a second stage operation, in 1 of them the permanent elephant trunk procedure was initially attempted but the second stage procedure was done because of increasing endo-leakage. The mean interval between operations was 8 days (range 1 to 14 days) in the remaining 8 patients. In 5 of 6 patients who underwent the permanent elephant trunk procedure, a decrease in the size of the aneurysm based on thromboexclusion was observed using serial computed tomography scans. A single stage repair was performed in 1 patient. The 30-day survival rate of all operations was 100%, however, there was 1 in-hospital death (6%) after the second operation. There was no stroke, however, paraplegia occurred after the first operation in 1 patient (6%) of the in-hospital death. No new phrenic or recurrent laryngeal nerve palsy occurred as a result of surgery.

CONCLUSIONS

The present technique using a modification of the elephant trunk technique for extensive aortic aneurysm provides acceptable mortality and morbidity. The present strategy would be an alternative for the standard elephant trunk procedure in some high-risk patients with advanced age and comorbidities.

Hepatic dysfunction after left ventricular mechanical assist in patients with end-stage heart failure: role of inflammatory response and hepatic microcirculation

BACKGROUND

In the condition of preexisting vital organ failure induced by heart failure, hepatic failure often progresses despite establishment of adequate hemodynamic support through a left ventricular assist device (LVAD) and results in a high mortality rate. We hypothesized that inflammatory responses, including those induced by infection and their influence on organ perfusion, may contribute to the pathogenesis of this progressive hepatic failure and subsequent multiple organ failure as reported in the current investigation on multiple organ failure after major surgery or trauma.

METHODS

Hepatic function and its relation to inflammatory response and hepatic microcirculation were evaluated in 16 consecutive patients who received an implantation of LVAD for end-stage cardiomyopathy, between 1992 and 2000. Patients were divided into two groups: 5 patients who died from multiple organ failure after severe hepatic failure (group 1) and 11 patients who did not develop severe hepatic failure (group 2). Serum levels of CRP, interleukin (IL)-6, IL-8, and serum hyaluronan, a known indicator of hepatic sinusoidal function, were measured pre- and postoperatively in both groups.

RESULTS

Serum ALT and AST levels during LVAD support were similar in the two groups. Serum total bilirubin (T-Bil), CRP, IL-6, and IL-8 levels before and during the first 20 days of LVAD support were significantly higher in group 1 than those in group 2 (p < 0.01 to 0.05). Serum hyaluronan levels in both groups were significantly correlated with T-Bil levels (r = 0.60, p < 0.05 in group 1; r = 0.68, p < 0.0001 in group 2). Histopathological examination by transvenous liver biopsy in a group 1 patient showed hepatic sinusoidal damage as well as cholestasis and fibrosis.

CONCLUSIONS

Patients with hyperbilirubinemia and inflammatory reactions before LVAD support showed increased hyperbilirubinemia and inflammatory cytokine and hyarulonan levels despite adequate hemodynamics achieved under LVAD support. These results suggest that inflammatory response contributes to subsequent aggravation of hepatic dysfunction, probably with underlying and continuing derangement in hepatic sinusoidal microcirculation even under systemic circulatory support.

Pulsatile perfusion improves regional myocardial blood flow during and after hypothermic cardiopulmonary bypass in a neonatal piglet model

Pediatric myocardial related morbidity and mortality after cardiopulmonary bypass (CPB) are well documented, but the effects of pulsatile perfusion (PP) versus nonpulsatile perfusion (NPP) on myocardial blood flow during and after hypothermic CPB are unclear. After investigating the effects of PP versus NPP on myocardial flow during and after hypothermic CPB, we quantified PP and NPP pressure and flow waveforms in terms of the energy equivalent pressure (EEP) for direct comparison. Ten piglets underwent PP (n = 5) or NPP (n = 5). After initiation of CPB, all animals underwent 15 minutes of core cooling (25 degrees C), 60 minutes of hypothermic CPB with aortic cross-clamping, 10 minutes of cold reperfusion, and 30 minutes of rewarming. During CPB, the mean arterial pressure (MAP) and pump flow rates were 40 mm Hg and 150 ml/kg per min, respectively. Regional flows were measured with radiolabeled microspheres. During normothermic CPB, left ventricular flow was higher in the PP than the NPP group (202+/-25 vs. 122+/-20 ml/l 00 g per min). During hypothermic CPB, no significant intragroup differences were observed. After 60 minutes of ischemia and after rewarming (276+/-48 vs. 140+/-12 ml/100 g per min; p < 0.05) and after CPB (271+/-10 vs. 130+/-14 ml/100 g per min; p < 0.05), left ventricular flow was higher in the PP group. Right ventricular flow resembled left ventricular flow. The pressure increase (from MAP to EEP) was 10+/-2% with PP and 1% with NPP (p < 0.0001). The increase in extracorporeal circuit pressure (ECCP) (from ECCP to EEP) was 33+/-10% with PP and 3% with NPP (p < 0.0001). Pulsatile flow generates significantly higher energy, enhancing myocardial flow during and after hypothermic CPB and after 60 minutes of ischemia in this model.

Global and regional cerebral blood flow in neonatal piglets undergoing pulsatile cardiopulmonary bypass with continuous perfusion at 25 degrees C and circulatory arrest at 18 degrees C

To investigate the influence of hypothermic cardiopulmonary bypass (HCPB) at 25 degrees C and circulatory arrest at 18 degrees C on the global and regional cerebral blood flow (CBF) during pulsatile perfusion, we performed the following studies in a neonatal piglet model. Using a pediatric physiologic pulsatile pump, we subjected six piglets to deep hypothermic circulatory arrest (DHCA) and six other piglets to HCPB. The DHCA group underwent hypothermia for 25 min, DHCA for 60min, cold reperfusion for 10 min, and rewarming for 40 min. The HCPB group underwent 15 min of cooling, followed by 60 min of HCPB, 10min of cold reperfusion, and 30 min of rewarming. The following variables remained constant in both groups: pump flow (150 ml/kg/min), pump rate (150 bpm), and stroke volume (1 ml/kg). During the 60-min aortic crossclamp period, the temperature was kept at 18 degrees C for DHCA and at 25 degrees C for HCPB. The global and regional CBF (ml/100g/min) was assessed with radiolabeled microspheres. The CBF was 48% lower during deep hypothermia at 18degrees C (before DHCA) than during hypothermia at 25 degrees C (55.2 +/- 14.3ml/100g/min vs 106.4 +/- 19.7 ml/100 g/min; p < 0.05). After rewarming, the global CBF was 45% lower in the DHCA group than in the HCPB group 48.3 +/- 18.1 ml/100g/min vs (87 +/- 35.9ml/100g/min; p < 0.05). Fifteen minutes after the termination of CPB, the global CBF was only 25% lower in the DHCA group than in the HCPB group (42.2 +/- 20.7 ml/100 g/min vs 56.4 +/- 25.8ml/100g/min; p = NS). In the right and left hemispheres, cerebellum, basal ganglia, and brain stem, blood flow resembled the global CBF. In conclusion, both HCPB and DHCA significantly decrease the regional and global CBF during CPB. Unlike HCPB, DHCA has a continued negative impact on the CBF after rewarming. However, 15 min after the end of CPB, there are no significant intergroup differences in the CBF.

Usefulness of the low profile "True 8" intra-aortic balloon pumping catheter for preventing limb lschemia

The most important limitation in the use of an intra-aortic balloon pumping (IABP) is the risk of vascular complications. Recently, an IABP catheter with an 8.0 French shaft and low profile that may decrease the risk of vascular morbidity has been developed. We evaluated the in vitro balloon performance and the prevention of limb ischemia in clinical use. An 8.0 French IABP catheter was compared with a standard 9.5 French catheter. Inflation time (IT), deflation time (DT), and changes in volume (V) generated by the balloon were measured during the pumping cycle in an experimental model. The inflation velocity (V/IT) and deflation velocity (V/DT) were calculated as parameters of balloon performance. At 120 bpm the V/IT and V/DT were 0.34 ml/msec and 0.28 ml/msec with the 8.0 French, and 0.33 ml/msec and 0.24 ml/msec with the 9.5 French catheter. Twelve patients with coronary artery disease, ranging in age from 41 to 87 years (mean, 66 years), who underwent IABP support, were divided into group 1 (8.0 French, n = 4) and group 2 (9.5 French, n = 8). Ankle-arm pressure index (API), lactate extraction ratio (LER) in the limb with IABP insertion, and cardiac index (CI) were measured at 1, 12, and 24 hours postoperatively. There were no major vascular complications and no counterpulsation related morbidity. There was no significant difference between the two groups with regard to age, duration of IABP support, and incidence of peripheral vascular disease and diabetes. The percentage of women patients was significantly higher in group 1 (100% vs. 25%), whereas body surface area was significantly smaller (1.45 +/- 0.14 vs. 1.68 +/- 0.12 m2). The API in group 1 were slightly higher than those in group 2 throughout the observed period (not significant). The LER and Cl showed no significant differences between the two groups. These results suggest that the 8.0 French IABP catheter with a low profile has an acceptable in vitro performance, and its clinical application may be effective in preventing limb ischemia in a high-risk subset of patients such as women and smaller patients.

Gastric intramucosal pH during lower body circulatory arrest under open distal anastomosis with selective cerebral perfusion in aortic arch repair

Selective cerebral perfusion (SCP) and open distal anastomosis (OD) with hypothermia has been used as a popular means for circulatory assistance in aortic arch surgery. Although SCP has become accepted for brain protection, the influence of OD accompanying circulatory arrest on lower body ischemia is not known. We studied gastric tonometry (gastric intramucosal pH [pHi]) to estimate splanchnic ischemia during OD, and its relationship to postoperative organ function. In five patients (pts) (range, 65-78 years; mean, 71 years; group OD) who underwent arch replacement using SCP and OD with moderate hypothermia (25 degrees C) during the period from March to August of 1999, pHi was measured precardiopulmonary bypass (pre-CPB), 30 min of CPB (CPB30), 10 min after OD (OD10), at end of CPB, and post-CPB. Eight pts (range, 52-78 years; mean; 66 years) who underwent standard CPB (33 degrees C) during the same period (coronary artery bypass surgery in six and valve surgery in two) served as controls (group C). In group OD, pHi was significantly decreased at OD10 (7.35 +/- 0.03 at CPB30 vs. 7.23 +/- 0.07 at OD10, p < 0.05) but recovered by the end of CPB (7.32 +/- 0.02). Creatinine clearance on the first postoperative day (1POD) was significantly (p < 0.05) lower in group OD (82 +/- 40 ml/min) than in group C (126 +/- 25 ml/min), although there was no significant difference in preoperative values between the two groups. The pHi at OD10 did not correlate with the duration of OD (range, 30-47 min; mean, 38 min), whereas pHi at OD10 significantly correlated with BUN (r = -0.973, p = 0.0054), Cr(r = -0.977, p = 0.0043), and CCr (r = 0.908, p = 0.0328) on 1POD. One patient in group OD developed paraplegia and renal failure postoperatively. His pHi at OD10 was severely decreased to 7.11. These results suggest that intraoperative monitoring of pHi may be useful for the evaluation of visceral organ ischemia during OD in arch replacement and may contribute to improved technique for circulatory assistance in aortic surgery.

A novel modification of elephant trunk technique using a single four-branched arch graft for extensive thoracic aortic aneurysm

Surgical repair for the extensive thoracic aortic aneurysm remains unsatisfactory, especially in elderly patients. We developed a total arch replacement with modified elephant trunk technique under moderately hypothermic cardiopulmonary bypass and selective brain perfusion, in which a 4-branched arch graft with a sewing 'collar' enabled the distal anastomosis just proximal to the innominate artery with open distal method and a long 'elephant trunk' was inserted into the descending aorta by the forceps catheter via the femoral artery. This modification is easy and less invasive, and reduces the risk of postoperative complications.

Pulsatile and nonpulsatile flows can be quantified in terms of energy equivalent pressure during cardiopulmonary bypass for direct comparisons

The purpose of this study was to quantify and compare pulsatile and nonpulsatile pressure and flow waveforms in terms of energy equivalent pressure (EEP) during cardiopulmonary bypass in a neonatal piglet model. EEP is the ratio of the area under the hemodynamic power curve and the flow curve. Piglets, mean weight of 3 kg, were used in physiologic pulsatile pump (n = 7), pulsatile roller pump (n = 6), and nonpulsatile roller pump (n = 7) groups. Data (waveforms of the femoral artery pressure, pump flow, and preaortic cannula extracorporeal circuit pressure) were collected during normothermic cardiopulmonary bypass at 35 degrees C (15 minutes on-pump), before deep hypothermic circulatory arrest (pre-DHCA) at 18 degrees C, and after cold reperfusion and rewarming (post-DHCA) at 36 degrees C. The pump flow rate was 150 ml/kg/min in all three groups. During pulsatile perfusion, the pump rate was 150 bpm in both pulsatile groups. Although there was no difference in mean pressures in all groups, EEP and the percentage increase of pressure (from mean pressure to EEP) of mean arterial pressure and preaortic cannula extracorporeal circuit pressure were higher with pulsatile perfusion compared with nonpulsatile perfusion (p < 0.001). In particular, the physiologic pulsatile pump group produced significantly higher hemodynamic energy compared with the other groups (p < 0.001). These results suggest that pulsatile and nonpulsatile flows can be quantified in terms of EEP for direct comparisons, and pulsatile flow generates higher energy, which may be beneficial for vital organ perfusion during cardiopulmonary bypass.

Effects of perfusion mode on regional and global organ blood flow in a neonatal piglet model

BACKGROUND

Organ injury (brain, kidney, and heart) has been reported in up to 30% of pediatric open heart surgery patients after conventional hypothermic non-pulsatile cardiopulmonary bypass (CPB) support with or without deep hypothermic circulatory arrest (DHCA). The effects of pulsatile (with a Food and Drug Administration approved modified roller pump) versus non-pulsatile perfusion on regional and global cerebral, renal, and myocardial blood flow were investigated during and after CPB with 60 minutes of DHCA in a neonatal piglet model.

METHODS

Piglets, mean weight 3 kg, were used in both pulsatile (n = 7) and non-pulsatile (n = 7) groups. After initiation of CPB, all animals were subjected to hypothermia for 25 minutes, reducing the rectal temperatures to 18 degrees C, 60 minutes of DHCA followed by 10 minutes of cold reperfusion and 40 minutes of rewarming with a pump flow of 150 mL/kg/min. During cooling and rewarming, alpha-stat acid-base management was used. Differently labeled radioactive microspheres were injected pre-CPB, on normothermic CPB, pre-DHCA, post-DHCA, and after CPB to measure the regional and global cerebral, renal, and myocardial blood flows.

RESULTS

Global cerebral blood flow was significantly higher in the pulsatile group compared to the non-pulsatile group at normothermic CPB (100.4 +/- 6.3 mL/100 gm/min versus 70.2 +/- 8.1 mL/100 gm/min, p < 0.05) and pre-DHCA (77.2 +/- 5.2 mL/100 gm/min versus 56.1 +/- 6.7 mL/100 gm/min, p < 0.05). Blood flow in cerebellum, basal ganglia, brain stem, and right and left cerebral hemispheres had an identical pattern with the global cerebral blood flow. Renal blood flow appeared higher in the pulsatile group compared to the non-pulsatile group during CPB, but the results were statistically significant only at post-CPB (94.8 +/- 9 mL/100 gm/min versus 22.5 +/- 22 mL/100 gm/min, p < 0.05). Pulsatile flow better maintained the myocardial blood flow compared to the non-pulsatile flow after CPB (316.6 +/- 45.5 mL/100 gm/min versus 188.2 +/- 19.5 mL/100 gm/min, p < 0.05).

CONCLUSIONS

Pulsatile perfusion provides superior vital organ blood flow compared to non-pulsatile perfusion in this model.

The effects of pulsatile versus nonpulsatile perfusion on blood viscoelasticity before and after deep hypothermic circulatory arrest in a neonatal piglet model

Blood trauma increases blood viscoelasticity by increasing red cell aggregation and plasma viscosity and by decreasing cell deformability. During extracorporeal circulation, the mode of perfusion (pulsatile or nonpulsatile) may have a significant impact on blood trauma. In this study, a hydraulically driven dual chamber pulsatile pump system was compared to a standard nonpulsatile roller pump in terms of changes in the blood viscosity and elasticity during cardiopulmonary bypass (CPB) and pre and post deep hypothermic circulatory arrest (DHCA). Piglets, with an average weight of 3 kg, were used in the pulsatile (n = 5) or nonpulsatile group (n = 5). All animals were subjected to 25 min of hypothermia, 60 min of DHCA, 10 min of cold reperfusion, and 40 min of rewarming with a pump flow of 150 ml/kg/min. A pump rate of 150 bpm, pump ejection time of 120 ms, and stroke volume of 1 ml/kg were used during pulsatile CPB. Arterial blood samples were taken pre-CPB (36 degrees C), during normothermic CPB (35 degrees C), during hypothermic CPB (25 degrees C), pre-DHCA (18 degrees C), post-DHCA (19 degrees C), post-rewarming (35 degrees C), and post-CPB (36 degrees C). Viscosity and elasticity were measured at 2 Hz and 22 degrees C and at strains of 0.2, 1, and 5 using the Vilastic-3 Viscoelasticity Analyzer. Results suggest that the dual chamber neonate-infant pulsatile pump system produces less blood trauma than the standard nonpulsatile roller pump as indicated by lower values of both viscosity and elasticity during CPB support.