Acute pulmonary embolectomy three days following a coronary artery bypass graft procedure.

Pulmonary embolism is very rarely reported early after cardiac surgery, most probably due to full heparinisation during cardiopulmonary bypass. We report a 66-year-old man without thromboembolic history who presented three days after a coronary artery bypass grafting procedure with acute dyspnoea and haemodynamic instability. A CT scan confirmed paracentral bilateral pulmonary embolism requiring an urgent and successful embolectomy. Review of the literature confirms that pulmonary embolism may occur in up to 3% of post-cardiopulmonary bypass patients. The possibility of pulmonary embolism must be taken into consideration in post-cardiopulmonary bypass patients with acute onset of chest pain and respiratory insufficiency.

Prolonged recovery and respiratory depression after fentanyl infusion in a sheep undergoing mitral valve reconstruction.

A sheep was anaesthetized for implantation of a novel device (MitroFast) to replace the posterior leaflet of the mitral valve. Anaesthetic management included a balanced anaesthetic protocol and consisted of propofol or isoflurane combined with fentanyl infusion (0.15-0.4 microg/kg/min). Deliberate hypothermia during cardiopulmonary bypass was set at 34.5-35.5 degrees C. Surgery proceeded uneventfully. Total time of aortic cross-clamping was 35 min and total time on extracorporeal circulation was 60 min. Visual inspection, intracardiac pressure testing and transesophageal echocardiography indicated proper functioning of the device. The anaesthetic period was uneventful, but recovery was prolonged with central nervous and respiratory depression and marked hypoxaemia. Administration of naloxone (1.5 microg/kg, repeated twice at 15-20 min intervals) reversed the central nervous and attenuated the respiratory depressions. An initially low rate of urine production normalized after rewarming and a single intravenous administration of furosemide.

Perioperative monitoring of flow and patency in native and grafted internal mammary arteries using a combined MR protocol.

The objective of this study was to evaluate graft flow (f) and patency (p) in patients with internal mammary artery (f,p) and venous (p only) grafts using a combined MR protocol with phase-contrast technique and MR angiography. 42 patients with 42 left internal mammary artery (LIMA) and 63 venous grafts were examined pre and 6 months post coronary artery bypass graft (CABG) surgery. Phase-contrast flow measurements were applied to the IMA. Post-operatively, a contrast enhanced MR angiogram was performed to assess bypass patency. LIMA/venous grafts were occluded in 3/42 and 13/63, respectively. Flow in LIMA decreased from 19.4+/-10.4 ml min(-1) m(-2) pre-operatively to 13.4+/-9.7 ml min(-1) m(-2) post-operatively (p<0.002). In contrast, flow in the native right IMA increased from 17.6+/-8.7 ml min(-1) m(-2) pre-operatively to 24.8+/-9.0 ml min(-1) m(-2) post-operatively (p<0.001). MRI allows a combined assessment of bypass patency and flow. This study protocol may be applicable to perioperative follow-up studies in patients after CABG surgery.

[The Sorin pericardial bioprosthesis--a stentless aortic valve with very good hemodynamic performance]. / Die Sorin Perikard-Bioprothese--eine Stentless Aortenklappe mit sehr guter hämodynamischer Leistung.

BACKGROUND: The Sorin Pericarbon Freedom Stentless aortic valve has the potential to provide superior hemodynamic function and durability. In this study we assessed the hemodynamic performance of this valve and its impact on LV-mass regression after aortic valve replacement. METHODS: 31 consecutive patients who received a Sorin Pericarbon Freedom Stentless aortic valve were analysed. Mean age of the patients (16 female and 15 male) was 64 +/- 17 years. Five patients had isolated aortic stenosis, three isolated aortic regurgitation and one combined aortic valve disease. Three patients had combined aortic and mitral valve disease, 14 patients concomitant coronary artery disease, one congenital aortic coarctation. Three patients had an acute aortic valve endocarditis. 18 patients were classified as high-risk patients (mean EuroSCORE 9 +/- 2). Mean left ventricular ejection fraction was 52.5 +/- 15.0%. RESULTS: Valve sizes from 21 mm to 29 mm were implanted. The valves were oversized by 2 mm compared to measurement. 16 patients received isolated aortic valve replacement, Three patients aortic valve replacement and mitral valve reconstruction. 12 patients had concomitant CABG. Three procedures were reoperations. Hospital mortality was 6.4% (two patients). Both deaths occurred in high-risk patients and were not valve-related. Four patients had perioperative low-output-syndrome and needed IABP. After six months a follow up echocardiography was performed. Mean and peak gradients were 9.6 +/- 4.4 and 20.6 +/- 5.9 mmHg, respectively. Significant reduction of left ventricular hypertrophy (LV mass index 126.5 +/- 27.3 vs. 189.6 +/- 45.3 g/m2, p = 0.0313) and improvement of the ejection fraction (58 +/- 9.8 vs. 52.5 +/- 15.0%, p = 0.9749) as compared with preoperative valve. CONCLUSIONS: The hemodynamic performance of the Sorin Pericarbon Freedom Stentless aortic valve is excellent and the patient outcome is satisfying. However the implantation technique requires longer ischemic time, the prosthesis offers very satisfying hemodynamic function and accelerates probably the LV-mass regression in the mid term follow-up. Late performance and durability of the valve have to be assessed.

Aprotinin reduces blood loss in off-pump coronary artery bypass (OPCAB) surgery.

OBJECTIVE: Effects of aprotinin in off-pump coronary artery bypass (OPCAB) surgery have not yet been described. This study analyses hemostasiologic changes and potential benefit in OPCAB patients treated with aprotinin. METHODS: In a prospective, double-blind, randomized study 47 patients undergoing OPCAB surgery were investigated. Patients received either aprotinin (2 x 10(6) KIU loading dose and 0.5 x 10(6) KIU/h during surgery, n=22) or saline solution (control, n=25). Activated clotting time was adjusted to a target of 250 s intraoperatively. Blood samples were taken up to 18h postoperatively: complete hematologic and hemostasiologic parameters including fibrinopeptide A (FPA) and D-dimer in a subgroup of 31 patients were analyzed. Blood loss, blood transfusion and other clinical data were collected. RESULTS: Both groups showed comparable demographic and intraoperative variables. Forty-one (87%) patients of the whole study group received aspirin within 7 days prior to surgery. Number of grafts per patient were comparable (2.9+/-1.0 [mean+/-SD] in the aprotinin group and 2.8+/-1.2 in control, P=0.83). Blood loss during the first 18 h in intensive care unit was significantly reduced in patients treated with aprotinin (median [25th-75th percentiles]: 500 [395-755] ml vs. 930 [800-1170] ml, P<0.001). Postoperatively only two patients (10%) in the aprotinin group received packed red blood cells, whereas eight (35%) in the control group (P=0.07). Perioperatively FPA levels reflecting thrombin generation were elevated in both groups. The increase in D-dimer levels after surgery was significantly inhibited in the aprotinin group (P<0.001). Early clinical outcome was similar in both groups. CONCLUSIONS: Aprotinin significantly reduces blood loss in patients undergoing OPCAB surgery. Inhibition of enhanced fibrinolysis can be observed. FPA generation during and after OPCAB surgery seems not to be influenced by aprotinin.

Isolated amelanotic malignant melanoma of the heart.

We report a 58-year-old woman presenting with dyspnoea and recurrent pulmonary embolism. Echocardiography revealed pericardial effusion and a tumour located in the atrioventricular groove. Surgical exploration showed tumorous infiltration of the ventricle wall and of parts of the atrium. Curative excision was not possible and the operation was discontinued. Histology revealed an amelanotic malignant melanoma. No other tumour location was detected by scanning procedures. This case represents a very rare manifestation of melanoma exclusively located in the atrioventricular groove of the heart leading to recurrent pulmonary embolism. A review of the literature on cardiac involvement of melanoma is provided.

[2D-phase contrast flow evaluation and contrast-enhanced MR angiography for perioperative assessment of internal mammary artery grafts]. / 2D-Phasenkontrast-Flussquantifizierung und kontrastangehobene 3D-MR-Angiographie zur perioperativen Untersuchung des Arteria-mammaria-interna-Bypasses.

PURPOSE: To evaluate LV functional parameters, graft flow and patency in patients with IMA grafts using a combined MR protocol with phase-contrast technique and contrast enhanced MR angiography. MATERIAL AND METHODS: Using a 1.5 T MR system 27 patients with 27 left internal mammary artery (LIMA) and 41 venous grafts were examined before and 6 months after CABG surgery. A T(1)w-TSE sequence (slice thickness 5 mm) was applied for morphological imaging. LV function (EF, CO) was evaluated on cine images (segmented FLASH 2D, TR(eff) 11 ms, TE 4.8 ms, flip angle 25 degrees ). A phase-contrast FLASH 2D (TR 24 ms, TE 5 ms, flip angle 20 degrees ) sequence was applied for aortic and IMA flow measurements. Postoperatively, a contrast enhanced FLASH 3D MR angiography (TR 3.8 ms, TE 1.4 ms, flip angle 30 degrees ) with 25 ml Gd-DTPA was performed to assess bypass patency. RESULTS: In patients with reduced LV function (ejection fraction < 50 %) an improvement of the ejection fraction from 38.4 +/- 10.3 % to 49.8 +/- 15.3 % (p < 0.05) was found postoperatively. LIMA grafts were occluded in 1/27 patients, while 6/41 venous grafts were occluded. Distal LIMA anastomoses were demonstrated in 33 % by MRA. Flow of LIMA decreased from 21.2 +/- 11 ml/min/m(2) preoperatively to 14.4 +/- 9.6 ml/min/m(2) postoperatively (p < 0.01). CONCLUSION: MR imaging allows accurate combined assessment of LV function, bypass patency and flow. The protocol of this study may be applicable for perioperative follow-up studies in patients after CABG surgery.

Minimizing aortic manipulation during OPCAB using the symmetry aortic connector system for proximal vein graft anastomoses.

BACKGROUND: Since minimal invasive techniques have become increasingly common in coronary artery bypass grafting (CABG), there has been renewed interest in facilitated mechanical anastomoses devices that might have the potential of replacing the standard suturing techniques in vascular anastomoses. We report our initial experience with the successful creation of mechanical proximal vein graft anastomoses in off-pump coronary artery bypass operations. METHODS: From August to December 2000, we investigated the first 20 consecutive patients who underwent CABG on the beating heart without extracorporeal circulation and who received at least one mechanical proximal vein graft anastomosis with the St. Jude Medical Symmetry aortic connector system without side-clamping of the aorta. We evaluated the different components of the system, the feasibility of such anastomoses, and the intraoperative flow measurements of the grafts using transit time methods. RESULTS: A total of 32 proximal vein graft anastomoses were performed with the aortic connector system. Hemostasis was instantaneous in all cases except one, in which the connector was removed and the anastomosis was hand-sewn without complications. All other vein grafts were patent at the end of the procedure; intraoperative flow measurements were 39 +/- 25 mL/min for single vein grafts (n = 20) and 69 +/- 25 mL/min for sequential grafts (n = 11). CONCLUSIONS: The St. Jude Medical Symmetry aortic connector system is a user-friendly, effective, quick, and reliable device for sutureless proximal vein graft anastomosis in CABG. This system allows the construction of uniform and geometrically perfect anastomoses and does not require aortic side-biting. This technology is attractive for all CABG procedures because aortic manipulation is reduced. In off-pump surgical procedures the connector system allows aortic manipulation to be minimized, potentially reducing embolization from aortic wall debris.

Constrictive tuberculous pericarditis in a HIV-positive patient.

Constrictive pericarditis is a relatively rare clinical manifestation nowadays. We present the case of an HIV-positive patient with constrictive calcified pericarditis due to an infection with Mycobacterium tuberculosis. Pericardectomy was performed. The therapeutical approach is discussed and the literature is reviewed.

Sutureless mechanical anastomosis of a saphenous vein graft to a coronary artery with a new connector device.

Construction of vascular anastomoses by manual suturing is a highly skilled and time-consuming procedure. The St Jude Medical Anastomotic Technology Group has developed a sutureless mechanical anastomosis device, which, when tested in animals, produced anastomoses in less than 3 min and with little training. Here we present the results of the first clinical saphenous-vein to coronary-artery anastomosis by means of this device.

Atherosclerotic disruption of the aortic arch during coronary artery bypass operation.

A 70-year-old-man presented with a symptomatic three vessel coronary artery disease and was scheduled for myocardial revascularization. During extracorporeal circulation an intrathoracal bleeding occurred and aortic rupture was suspected. An iatrogenic plaque rupture in the concavity of the aortic arch was found due to cannulation attempts. The aortic arch was grafted in the so-called elephant trunk technique. Thereafter bypass grafts were anastomosed to the stenosed coronary arteries. The patient was discharged from hospital after 2 weeks in good condition.

[The MR signal behavior of a 4-week-old occlusive myocardial infarct in an animal experiment]. / MR-Signalverhalten des 4 Wochen alten okklusiven Myokardinfarktes im Tierexperiment.

PURPOSE: To correlate signal behaviour in T1- and T2-weighted images after Gd-DTPA with regional histopathology in occlusive myocardial infarction (MI). METHODS: Ligation of a diagonal branch of the LAD was performed in seven sheep. Four weeks later 0.1 mmol Gd-DTPA/kg were injected in five sheep 15 min before cardiac arrest and the sheep were slaughtered. In vitro imaging was performed at 1.5 T included T1- and T2-weighted spin echo sequences in long and short axis views. Signal intensities (SI) were determined in 36 myocardial segments per slice and compared to macro- and microscopy. RESULTS: In all animals an antero-lateral infarct region was evident histologically. This region presented with increased T2 SI and T1 SI after Gd-DTPA. The number of segments with increased SI in T1-weighted images was higher (n = 195 segments) compared to segments with increased T2 SI (n = 122 segments). Granulation tissue could be differentiated from rarely vascularized connective tissue at a high level of significance (p < 0.001) by T1 and T2 SI analysis. Wall thickness was significantly decreased in necrotic myocardium (3.8 +/- 1.2 mm) compared to normal tissue (9.8 +/- 1.1 mm, p < 0.001). CONCLUSION: In four-week-old occlusive MI the extent of necrosis can be accurately assessed by analysis of post contrast T1-weighted images. Considering regional T2 SI, granulation tissue can be differentiated from regions with predominant fibrous organisation.

Successful weaning of a transplanted heart from biventricular assist device.

Exceptionally few cases worldwide have survived weaning from a biventricular assist device following heart transplantation in contrast to those who underwent early retransplantation. We present a successful outcome after biventricular assist device implantation following initial biventricular failure after heart transplantation. Weaning could be performed after 1 week, although pulmonary vascular resistance remained markedly elevated.

The significance of preformed aprotinin-specific antibodies in cardiosurgical patients.

UNLABELLED: Acute hypersensitivity reactions are serious complications of reexposure to aprotinin. Previous contact via infusions or fibrin tissue adhesives can induce specific antibodies. In this study, we aimed to elucidate the preoperative prevalence of aprotinin-specific antibodies in patients scheduled for cardiac operations. Sera of 520 consecutive cardiosurgical patients were collected preoperatively and screened retrospectively for aprotinin-specific IgG using a standard enzyme-linked immunosorbent assay (ELISA). Positive sera were analyzed also for aprotinin-specific IgA (ELISA) and IgE (fluorescence enzyme immunoassay). The histories of all patients were reviewed with focus on aprotinin preexposure. Of 520 patients, 22 (4%) had specific IgG. Only three of these had a documented aprotinin preexposure. Of 448 patients exposed to aprotinin intraoperatively, 15 had preformed specific antibodies. The only patient presenting with severe anaphylaxis was positive for both IgG and IgE, and had a recent IV preexposure in cardiovascular surgery. The presence of aprotinin-specific IgG alone seems not to induce adverse reactions on exposure. Exposure history alone is not sensitive enough to identify patients with aprotinin-specific antibodies. IMPLICATIONS: Anaphylaxis on IV reexposure to aprotinin is a medical emergency. The clinical significance of preformed aprotinin-specific IgG remains questionable, whereas preformed IgE was present in the only patient who suffered from severe anaphylaxis on reexposure to aprotinin. Preformed antibodies are not reliably predicted by exposure history.

Transmyocardial laser revascularization with the Holmium:YAG laser does not improve myocardial perfusion in the acutely ischemic heart: an experimental study measuring myocardial perfusion by a thermal imaging camera.

BACKGROUND: Transmyocardial laser revascularization (TMLR) is a new surgical therapy for patients with end-stage coronary artery disease refractory to conventional therapy. TMLR should act by improvement of perfusion of the lasered myocardium. Blood should be delivered from the cavity of the heart to the surface of the myocardium. The aim of this study was to measure perfusion of normal, ischemic, and ischemic myocardium after TMLR. METHOD: We used a new method of perfusion measurement by an infrared thermal imaging system in an open-chested adult sheep model with temporary and permanent occlusion of the dominant diagonal branch. RESULTS: A significant fall from normal perfusion of the myocardium to reduced after inducing ischemia (p<0.01) and a significant rise again after reperfusion (p<0.001) could be shown. Perfusion measurements after TMLR did not significantly differ from perfusion measurements after inducing ischemia (p=0.2). CONCLUSION: In the presented sheep model, laser revascularization could not improve myocardial perfusion after acute ischemia as seen by the infrared thermal imaging system.

Increased coagulation and bradykinin-release in shed pleural blood during cardiac surgery.

Retransfusion of shed pleural blood is generally believed to contribute to a decrease of intraoperative blood requirements, however, hemodynamic or hemostatic side effects are nevertheless still controversial. Some 13 patients (age: 58 +/- 11) undergoing CPB surgery including the use of the internal mammaria artery (IMA) were investigated. For IMA preparation, pleura of the left hemithorax was opened, allowing blood to accumulate within the pleural cavity. Some 472 +/- 258 ml blood volumes were retransfused after 79 +/- 11 min clamp time. After 50 +/- 15 s, mean arterial blood pressure (AP) dropped from 68 +/- 15 to 36 +/- 8 mm Hg, and the calculated systemic vascular resistance (SVR) decreased from 1124 +/- 263 to 596 +/- 153 dyn s(-1) cm5 (p < 0.01). Bradykinin levels in the retransfused shed blood showed significantly higher values (205 +/- 88 fmol/ml) compared to the systemic blood (24 +/- 19 fmol/ml). Thrombin-antithrombin-III complexes were strongly elevated in the shed pleural blood, and after retransfusion the systemic blood values increased significantly. After retransfusion of shed pleural blood during CPB an acute drop in AP and SVR occurred, probably caused by high bradykinin concentrations. We therefore recommend that the accumulation of shed blood is avoided by continuous retransfusion as is now the standard procedure in our University hospital.

Resection of a large right atrial hemangioma in a neonate after prenatal diagnosis.

Cardiac hemangiomas are extremely rare benign tumors. We describe the case of a right atrial hemangioma in a neonate diagnosed prenatally and successfully operated 10 days after spontaneous delivery. This unusual case illustrates the importance of prenatal diagnosis and delivery of the baby next to a pediatric center with a department of appropriately specialized cardiovascular surgery.

Aprotinin in fibrin tissue adhesives induces specific antibody response and increases antibody response of high-dose intravenous application.

BACKGROUND: In cardiac operations, aprotinin therapy is used either locally as a component of commercially available fibrin tissue adhesives, intravenously, or combined. Our aim was to examine the formation of aprotinin-specific antibodies with regard to the application mode. METHODS: Sera of 150 patients who had undergone cardiac operations and were receiving aprotinin therapy for the first time were sampled before the operation and at medians of 3.5 and 13.3 months after the operation. Aprotinin-specific IgG including all subgroups and aprotinin-specific IgE were analyzed. Aprotinin was given locally (as contained in fibrin sealant; n = 45; median dose, 6000 KIU), intravenously (n = 46; 2.000 x 10(6) KIU), and combined (n = 59; 2.012 x 10(6) KIU). RESULTS: At 3.5 months, the prevalence of aprotinin-specific IgG antibodies was 33% (15/45 patients) after local, 28% (13/46 patients) after intravenous, and 69% (41/59 patients) after combined exposure (P =.0001). At 13.3 months, the prevalence of aprotinin-specific IgG antibodies was 10% (4/41 patients) after local, 31% (13/42 patients) after intravenous, and 49% (28/57 patients) after combined exposure. Total aprotinin dose was similar in patients who were antibody positive and negative. Before the operation, no aprotinin-specific antibodies were detected. Aprotinin-specific IgE were not found after the operation. CONCLUSION: Local aprotinin contact induces a specific immune response and reinforces that of intravenous exposure. The antibody spectrum is identical to the immune response induced by intravenous exposure. Any exposure should be documented. For use in cardiac operations as a hemostyptic, the necessity itself and alternatives for aprotinin as a stabilizing agent merit consideration.

Transmyocardial laser revascularization in the acute ischaemic heart: no improvement of acute myocardial perfusion or prevention of myocardial infarction.

OBJECTIVE: Transmyocardial laser revascularization (TMLR) has been used to provide enhanced myocardial perfusion in patients not suitable for coronary revascularization or angioplasty. This study investigates the acute changes in myocardial perfusion after TMLR with a Holmium:Yttrium-Aluminium-Garnet (YAG) laser with a thermal imaging camera in a model of acute ischaemia, and confirms its midterm effects by post-mortem investigation of magnetic resonance imaging and histopathological examination. METHODS: Acute myocardial ischaemia was induced by occlusion of the dominant diagonal branch in ten sheep. Perfusion measurements were undertaken first in the unaffected myocardium, then after temporary occlusion of the coronary to obtain a control measurement for ischaemic myocardium. Myocardial perfusion was then evaluated during reperfusion after release of coronary occlusion. Then the coronary was permanently occluded and 20.5+/-2 channels were drilled with the Holmium:YAG laser and perfusion was measured again. The other four sheep served as control with untreated ischaemia. All animals were sacrificed after 28 days following administration of gadolinium i.v. to serve as contrast medium for magnetic resonance tomography. The hearts were subjected to magnetic resonance tomography and histopathological examination. RESULTS: Intraoperative perfusion measurements revealed a decreased perfusion after temporary occlusion and an increased perfusion in reperfused myocardium. After TMLR, no improvement of myocardial perfusion above the ischaemic level could be shown. Magnetic resonance images could neither confirm patent laser channels nor viable myocardium within ischaemic areas. On histology no patent endocardial laser channel could be detected. The transmural features were myocardial infarct with scar tissue. CONCLUSIONS: In the presented sheep model with acute ischaemia, TMLR with a Holmium:YAG laser did not provide acute improvement of myocardial perfusion as assessed by a thermal imaging camera. This would suggest no direct contribution of newly created laser channels to myocardial perfusion. As chronic effects are concerned, no perfused laser channels could be identified by later magnetic resonance imaging or histology.

[Diagnosis of renal artery stenosis in 1.0 T using 3D phase contrast magnetic resonance angiography and dynamic contrast medium perfusion]. / Diagnostik von Nierenarterienstenosen bei 1.0 T mittels 3D-Phasenkontrast-MR-Angiographie und dynamischer Kontrastmittelanflutung.

PURPOSE: To assess renal artery stenosis (RAS) by 3D phase contrast (PC) MR angiography and dynamic perfusion imaging of the kidneys. METHODS: On a standard 1.0 T MR imaging system (Magnetom Expert, Siemens), 32 patients with angiographically proven unilateral RAS were examined using a 3D PC sequence (TR 40 ms/TE 9 ms/venc 30 cm/s). An ECG-gated Turbo-FLASH 2D sequence (TR 4.5 ms/TE 2.2 ms/TIeff. 400 ms) was applied to study the first pass of paramagnetic contrast agent (0.1 mmol Gd-DTPA/kg) through the kidneys. Signal intensity (SI) over time curves of the renal cortex were obtained and evaluated considering temporal relation and percentage of maximum SI compared to the aorta and normal kidneys. Analysis of the MRA was performed by two independent blinded readers. The gold-standard DSA was interpreted by consensus reading of two experienced radiologists. RESULTS: RAS was detected by 3D PC MRA with a sensitivity of 93% and specificity of 81% (ppv 82%, npv 93%, accuracy 87%, kappa = 0.61). Maximum SI in RAS was significantly decreased (p < 0.001-0.0001). A temporally delayed enhancement of 1.5 +/- 1.3 s was found for RAS > 75% (p < 0.002) but not for RAS < 75% (p > 0.1). CONCLUSIONS: 3D PC MRA is capable of detecting RAS in a high percentage of patients. Dynamic perfusion imaging of the kidneys, applied additionally, can confirm the diagnosis and give valuable information about the hemodynamic relevance of RAS in suspected unilateral disease.