Functional outcome after myocardial revascularization in ischemic left ventricular failure

BACKGROUND: Myocardial revascularization in patients with left ventricular failure (ejection fraction < 30%) offers survival comparable to heart transplantation. The functional outcome, however, has yet to be determined. In order to assess the clinical results in patients with LVEF < 30% undergoing coronary artery bypass grafts (CABG), 101 consecutive patients operated between 1/91 and 1/97 were reviewed retrospectively. METHODS: The patients were stratified according to presentation: 65 pts had angina (Group 1) and 36 congestive failure (Group 2). Mean age (62 +/- 7 vs 60 +/- 8 yrs), sex (90 vs 88% male), LVEF (0.28 +/- 0.04 vs 0.29 +/- 0.04), prior myocardial infarction (1.2 +/- 0.4 vs 1.2 +/- 0.5 episodes/pt), presence of vital myocardium at scintiscan or low-dose dobutamine echocardiography (92 vs 93%), need for preoperative IABP (3.1 vs 8.3%), aortic cross-clamp (53 +/- 21 vs 60 +/- 21 min) and cardiopulmonary bypass (104 +/- 31 vs 114 +/- 36 min) times were comparable. RESULTS: There was only 1 (1%) perioperative death due to low-output syndrome. Eleven pts (6 vs 5, Group 1 vs Group 2) had postoperative low-output syndrome, requiring IABP in 7 pts (4 vs 3). There were 14 (10 vs 4, Group 1 vs Group 2) deaths during follow-up (29 +/- 19 months, range 2-67), with an overall actuarial survival of 91 +/- 4 vs 100% at 1 yr and 74 +/- 9 vs 78 +/- 10% at 5 yrs in Group 1 vs Group 2, respectively (p = ns). Actuarial symptom-free survival was 89 +/- 4 vs 84 +/- 6% at 1 yr and 49 +/- 9 vs 28 +/- 11% at 5 yrs, respectively (p = 0.05). Despite the high recurrence of congestive failure (22 vs 66% in Group 1 vs Group 2, p = 0.004), improvement in functional class (3.1 +/- 0.8 vs 1.5 +/- 0.7 in Group 1 and 2.7 +/- 0.7 vs 1.8 +/- 0.5 in Group 2) and LVEF (0.28 +/- 0.04 vs 0.38 +/- 0.04 in Group 1 and 0.29 +/- 0.04 vs 0.40 +/- 0.06 in Group 2) was found in both groups at follow-up. CONCLUSIONS: In spite of improving early and late survival after revascularization for ischemic left ventricular failure, patients presenting with congestive failure have an unsatisfactory symptom-free survival. Further studies are necessary to ascertain the relative indications to revascularization or transplantation in this specific patient subgroup.     

Improvement in exertional left ventricular dysfunction after revascularization

The case is reported of a 63-year-old white man with mild angina pectoris, whose systolic pressure fell 30 mmHg (4-0 kPa) with maximal exercise, without chest pain but with accompanying dizziness. Grafting the internal mammary arteries into the mid left anterior descending and obtuse marginal arteries improved regional myocardial perfusion and increased maximal cardiac output 24 per cent and maximal systolic pressure 32 per cent.     

Transhiatal closure of right-sided esophageal rupture after a left pneumonectomy

Right-sided spontaneous esophageal rupture developed 2 days after left pneumonectomy and vomiting. To avoid contamination of the pneumonectomized left thoracic cavity as well as a contralateral thoracotomy, we used a transhiatal approach for primary repair of the rupture, combined with right-sided pleural and mediastinal drainage, gastrostomy, and feeding jejunostomy. The 7-day barium meal control showed healing of the rupture.     

Improvement in exercise performance after unsuccessful myocardial revascularization

Two types of mechanosensitive units were found in the parenchyma of the rat mammary gland (SA and RA). Most of SA units had a spontaneous activity 1-3/sec. and responded to an abrupt displacement with a decline in the activity for 5-10 sec. RA had no such a response. The relation between average firing rate and displacement velocity at a constant displacement amplitude was linear for both SA and RA. RA however had the velocity threshold higher than SA. The number and frequency of SA afferent impulses decreased at a repeated stimulation. Electron microscopy revealed that free nerve endings correspond to SA and RA.     

Completion right lower lobectomy for recurrence after left pneumonectomy for metastases

Resection of pulmonary recurrences on the residual lung after pneumonectomy for metastases is exceptional. A 37-year-old woman was submitted to left extended pleuro-pneumonectomy after left leg amputation for fibrosarcoma. At 43 months later, a wedge resection on the right lower lobe was performed followed 32 months later by a further wedge resection in the same lobe. A completion right lower lobectomy for a new recurrence was performed 17 months after the last pulmonary resection. The patient did not develop postoperative complications. She is still alive and free of disease 10 years and 9 months after pneumonectomy and 36 months after completion lobectomy on the residual lung. In highly selected patients, aggressive surgery for metastases on the residual lung can be successfully performed and it can improve survival.     

Lung-heart ratio in stress thallium myocardial perfusion imaging in patients with a history of a previous pneumonectomy

Increased TI-201 lung-heart ratio after treadmill exercise or pharmacologic stress is an indicator of left ventricular dysfunction. After pneumonectomy, it is not reliable because of increased pulmonary circulation in the remaining lung. The authors present an example of normal stress TI-201 myocardial perfusion imaging with an increased lung-heart ratio of TI-201 uptake.     

Surgical myocardial revascularization

In conclusion, surgical myocardial revascularization has utilized diverse methods to increase blood flow to the starving myocardium. These methods initially used the microcirculation as the portal to reach myocytes until angiography showed that the obstructions were macrovascular. This resulted in a 30-year era of direct attack on the coronary blockages by coronary bypass. Surgical conduits unfortunately have longevity considerably less than that of native arteries and are limited in number. Alternative conduits, both biologic and prosthetic, have not yet proved to have the same clinical results as the ITA. More patients are living long enough to have the extensiveness of their disease exhaust conventional therapies. Newer therapy, restricted thus far to untreatables, revisits the microcirculation by making laser channels. These many innovative procedures have benefited hundreds of thousands of patients. They emerged from the probity and innovation of many individual surgeons.     

Transthoracic forequarter amputation and left pneumonectomy

As survival improves in patients with sickle cell anemia, the prospects of performing cardiac surgical procedures on older patients with this genetic defect increase. We describe the successful management of a 52-year-old patient with sickle cell disease (homozygous for hemoglobin S) and a history of multiple sickle crisis undergoing cardiopulmonary bypass for mitral valve repair. Preoperative partial exchange transfusion followed by total exchange transfusion at the time of operation was performed to reduce the level of hemoglobin S to 5.4% during bypass. Other management strategies included high-flow normothermic bypass with aortic crossclamping, topical hypothermia, and cold crystalloid cardioplegia.     

Transmyocardial laser revascularization fails to prevent left ventricular functional deterioration and aneurysm formation after acute myocardial infarction in sheep

OBJECTIVE: Transmyocardial laser revascularization is an investigational technique for revascularizing ischemic myocardium in patients with inoperable coronary arterial disease. This study tests the hypothesis that laser revascularization prevents left ventricular functional deterioration and aneurysm formation after acute anteroapical myocardial infarction. METHODS: An ultrasonic ascending aortic flow probe and snares around the distal left anterior descending and second diagonal coronary arteries were placed in 26 Dorsett hybrid sheep. Ten to 14 days later, snared arteries were occluded to produce an anteroapical infarction of 23% of left ventricular mass. Before infarction 14 animals had 34 +/- 4 transmyocardial perforations in the area of the anticipated infarction made with a carbon dioxide laser. Twelve animals served as controls. Hemodynamic measurements and transdiaphragmatic quantitative echocardiograms were obtained before, immediately after, and 2, 5, and 8 weeks after infarction. Eighteen sheep completed the protocol. RESULTS: All animals had large anteroapical left ventricular aneurysms with massive ventricular enlargement. Immediately after infarction the anterior wall became thinner and dyskinetic in all sheep. At 8 weeks aneurysmal size and shape were indistinguishable between groups. Two days after infarction, laser holes were filled with fibrin. At 5 and 8 weeks the infarct consisted of dense collagen, fibroblasts, scattered calcifications, myocyte fragments, neutrophils, macrophages, and no laser holes. There were no significant differences at any time between groups for cardiac pressures or output, ventricular volumes, ejection fraction, stroke work, and the stroke work-left ventricular end-diastolic pressure index. CONCLUSION: Transmyocardial laser perforations do not revascularize acute myocardial infarction in sheep.     

Influence of carotid atheroma on the neurologic status after myocardial revascularization

Surgical management of the carotid disease remains controversial in patients affected with coronary artery atheromatous disease. We report the Montreal Heart Institute experience on the influence of carotid disease on postoperative neurologic events of 501 consecutive patients operated on for coronary revascularization during the period from January 1994 to December 1994. There were 381 men and 114 women averaging 62 +/- 9 years old. Major risk factors were high blood pressure (35%), and smoking habit (48%). Fifty-nine patients presented clinical signs of carotid atheromatosis and among them 21 had significant carotid stenosis (> 80% decrease of cross sectional area). During surgery, the mean duration of extracorporeal circulation (ECC) was 76 +/- 31 minutes and the mean perfusion pressure (MPP) was 70 +/- 11 mmHg. The use of inotropic drugs was mandatory in 26% of the cases and the mean arterial lactate (AL) dosage during ECG was 3.07 +/- 1.35 mM/L. During the perioperative period, 13 (2.5%) patients sustained neurologic disturbances of which 5 (1%) were lateralized. Among them, 8 completely recovered whereas 3 of the 5 with permanent damage died. None of the patients with preoperative stigmata of carotid disease experienced lateralized neurologic deficit. Multivariate regression analysis identified the use of vasopressor drugs and perioperative increase of AL as predictive factors. We conclude that in our series, the incidence of neurologic complications was low. The presence of carotid atheromatosis did not increase the postsurgical risk of cerebrovascular accident, however, the increased incidence of neurologic events associated with inotropic drugs and increased AL suggests a direct link with a systemic oxygen debt. Consequently, we do no recommend concurrent prophylactic surgery during coronary artery revascularization.     

Results of left atrioventricular valve reconstruction after previous correction of atrioventricular septal defects

OBJECTIVE: The objective of this study was to determine causes of severe left atrioventricular (AV) incompetence and the factors leading to the success of valve repair later after correction of atrioventricular septal defects (AVSD). METHODS: A total of 28 patients aged 5 months to 38 years (mean age 6.7 years) were operated for significant (grade II-III) left AV valve incompetence (LAVVI), two months to twenty-five years (median 1.5 years) after correction of complete (11 patients) or partial atrioventricular septal defects. Fourteen patients had initially undergone surgery during infancy. RESULTS: At reoperation a completely open or partially sutured cleft was found in 16 patients combined with dysplastic valve tissue in four cases, with a fibrotic valve in three cases, with posterior leaflet prolapse in two cases, with a double orifice valve in three cases, and a parachute valve in two cases. Partial or complete reopening of a previously sutured cleft caused by suture dehiscence was found in 12 cases combined with a fibrotic valve in five cases, with a dysplastic valve in one case and with severe deformity of valve in one case. A combination of these anomalies was observed in seven patients in both groups. Left atrioventricular valve repair including cleft closure combined with annuloplasty and other surgical procedures resulted in the disappearance or significant diminishing of LAVI in 18 patients (64%). Severe SAVI persisted in six patients, five of them exhibiting a combination of several additional left AV valve anomalies (fibrotic or dysplastic valve, parachute valve). Five of these six patients underwent successful left AV valve replacement with a mechanical prosthesis 7 days to 2 years after reoperation. The presence of additional left AV valve anomalies was the single statistically significant factor for recurrent major LAVVI after reoperation (P = 0.0106). There were two postoperative deaths in patients with mild LAVVI after surgery, and no late deaths. CONCLUSION: An open cleft is the major factor of late severe SAVVI after correction of AVSD. Although suturing the cleft in conjunction with performing annuloplasty improved valvular function in most of the cases, the presence of severe left AV valve anomalies increased the risk of recurrent LAVVI and the need for valve replacement, thus playing a major role in determining the outcome of valve reconstruction in patients after reoperation.     

Cardiac hernia after intrapericardial pneumonectomy

Cardiac herniation secondary to intrapericardial pneumonectomy is a rare complication, although its real incidence has surely been underestimated. We describe a patient with left cardiac herniation presenting after intrapericardial pulmonectomy for primary lung cancer. The signs were severe hemodynamic shock requiring additional surgery involving a wide opening in the pericardium. The outcome after surgery was fully satisfactory.     

Routine broncho-myo-plasty after pneumonectomy]

Bronchopleural fistula is certainly the most important and specific complication following total pneumonectomy. In order to reduce this risk a systematic protection of bronchial suture by means of muscular flap transposition is suggested. The authors report 15 cases of total pneumonectomy for lung cancer at different localization. In all the patients a bronchomuscular plasty was used to protect the bronchial suture. The anterolateral body of latissimus dorsi, when it was possible, was preferred for the following reasons: 1) it makes the suture of the main bronchus greatly resistant; 2) it makes easier the obliteration of the pleural cavity; 3) its transposition is rapid and easy. In only one case a diaphragmatic flap was transposed together with its vascular and nervous system giving rise to a phrenic paralysis. Although few cases are reported, the results are successful and encourage the application of this procedure in future.     

Prolonged myocardial hibernation exacerbates cardiomyocyte degeneration and impairs recovery of function after revascularization

OBJECTIVES: We sought to define the effects of time on contractile function, morphology and functional recovery after coronary revascularization in patients with dysfunctional but viable (hibernating) myocardium. BACKGROUND: Functional recovery after coronary artery bypass graft surgery in patients with chronic myocardial hibernation is incomplete or delayed. The proposed cause is a progressive temporal degeneration of cardiomyocytes. METHODS: In 32 patients with multivessel coronary disease, regional wall motion analysis was performed in hypoperfused but metabolically active areas before and 6 months after bypass surgery. During bypass surgery, transmural biopsy samples were obtained from the center of the hypokinetic zone for light and electron microscopic analyses. The proposed duration of myocardial hibernation was retrospectively assessed. RESULTS: Patients with a subacute hibernating condition (<50 days) demonstrated a higher preoperative ejection fraction (EF, 50+/-8%), and a better preserved wall motion (WM) in the supraapical wall (-1.4+/-0.4) than did patients with intermediate-term (>50 days, EF 37+/-9%, p < 0.05; WM -2.4+/-1.5, p = 0.08) or chronic (>6 months, EF 40+/-14%, WM -2.7+/-0.9, p < 0.005) ischemia. Structural degeneration correlated with the duration of ischemia (r = 0.56, p < 0.05). Postoperative recovery of function was enhanced in patients with a short history of hibernation compared with patients with an intermediate-term or chronic condition (EF 60+/-10% vs. 40+/-10%, p < 0.001, and vs. 47+/-14%, p < 0.05). CONCLUSIONS: Hibernating myocardium exhibits time-dependent deterioration due to progressive structural degeneration with enhanced fibrosis. Early revascularization should be attempted to salvage the jeopardized tissue and improve postoperative outcome.     

Reduced left ventricular relaxation velocity after acute myocardial infarction

The full length porcine granulocyte/macrophage colony stimulating factor (GM-CSF) cDNA, including secretion signal peptide coding region was recloned into baculovirus transfer vector pAcYM1. The vector was then transfected with Autographica californica nuclear polyhedrosis virus (AcNPV) DNA into SF21AE cells and the recombinant virus AcPGM was recovered. Recombinant porcine GM-CSF (rpGM-CSF) was obtained from the serum-free culture medium of Tn5 cells infected with the AcPGM virus, and was shown to be a glycosylated 21 kDa protein as confirmed by tunicamycin treatment and [3H]-glucosamine uptake. The biological activities of rpGM-CSF in AcPGM-infected cell culture supernatants were demonstrated by porcine bone marrow cell proliferation and haematopoietic cell colony formation assays. The use of rpGM-CSF enabled us to culture porcine monocytes/macrophage and dendritic-like cells, derived from either porcine bone marrow or peripheral blood, for up to 4 months.     

Severe myocardial dysfunction and coronary revascularization

Severe myocardial dysfunction, characterized by global hypokinesis, or akinetic areas with hypokinesis of the remaining wall, and a very low ejection fraction (EF), has been considered to be a contraindication for coronary revascularization (CABG). However, myocardial scintigraphy and echo-stress data have shown that hypo- or akinetic areas can regain their contractility. Therefore, we expanded the indications for CABG, and performed operations even upon patients who were waiting for a heart transplant. Between January 1993 and June 1995, among 352 patients who underwent CABG, 85 had highly depressed left ventricular function. Their resting EF was lower than 0.35, and in 27 it was lower than 0.25. Viable areas of myocardium were found in all of the patients through the combination of scintigraphy and dobutamine-echocardiography: these areas depended on significant coronary lesions. The mean age of the patients was 48.2 years (range 33-62 years); angina was present in 62 patients. A mean of 3.1 grafts/patient were implanted; enoximone was used in all but 5 patients upon weaning from cardiopulmonary bypass; intra-aortic balloon pump was used in 9 cases. Operative mortality was 10.6% (9 patients), due to low-output syndrome in 5, acute myocardial infarction in 2, cerebral damage in 1, and respiratory failure in 1. At the 6-month follow-up, EF was improved in all but 7 patients, in whom it remained unchanged. Scintigraphic and echocardiographic tests revealed good function in most of the areas that had been previously recognized as hypo- or akinetic. These results suggest that the indications for standard myocardial revascularization can be expanded, and a promising option can be offered to patients who may otherwise be destined to wait for an uncertain transplantation.     

Coronary arterial anatomy in patients with left ventricular systolic dysfunction without chest pain or previous myocardial infarction

Patients with left ventricular systolic dysfunction without chest pain or previous myocardial infarction are unlikely to have 3-vessel coronary artery disease and are very unlikely to have coronary anatomy suitable for bypass grafting. Of our 108 subjects, only 3 (3%) had 3-vessel coronary artery disease thought to be suitable for revascularization.     

One-year effect of myocardial revascularization on resting left ventricular function and regional thallium uptake in chronic CAD

It is still unclear whether in patients with chronic coronary artery disease (CAD) the improvements in myocardial perfusion and left ventricular (LV) function induced by revascularization persist in the long run. This study was planned to evaluate the 1-yr effects of successful revascularization on myocardial perfusion and LV function in patients with CAD and to assess the accuracy of thallium imaging in the prediction of functional recovery 1 yr after revascularization. METHODS: Thirty-eight patients with chronic CAD who were revascularized (experimental group) underwent, while off drugs, 201Tl tomography, two-dimensional echocardiography and radionuclide angiography before and after a 1-yr follow-up. Twenty-nine patients with similar characteristics who were not revascularized (control group) and completed the 1-yr follow-up were also studied. Regional thallium activity was quantitatively measured in 13 segments per patient. Systolic function was assessed by echocardiography in corresponding segments. RESULTS: In the experimental group, at baseline, on the basis of regional LV function and thallium uptake, 276 segments were normal, 169 dysfunctional-viable and 49 nonviable. After revascularization, the majority (75%) of the dysfunctional-viable segments at baseline showed functional recovery at follow-up, whereas the majority (81%) of the nonviable segments at baseline did not. Simultaneously, LV ejection fraction increased 4 wk after revascularization (from 39% +/- 9% to 42% +/- 10%, p < 0.01) and remained unchanged after 1-yr (43% +/- 8%, p < 0.01 versus baseline study). LV wall-motion score index after 1 yr was reduced (from 1.68 +/- 0.4 to 1.42 +/- 0.3, p < 0.001) as compared with baseline. On the contrary, in the control group, no change in myocardial perfusion and LV function was detected after the 1-yr follow-up. CONCLUSION: In patients with chronic CAD, successful coronary revascularization induces a stable improvement in myocardial perfusion and LV function, which is still detectable after a 1-yr follow-up. Furthermore, preserved thallium uptake in dysfunctional regions is predictive of functional recovery after revascularization.     

Comparison of myocardial contrast echocardiography and low-dose dobutamine stress echocardiography in predicting recovery of left ventricular function after coronary revascularization in chronic ischemic heart disease

BACKGROUND: Dobutamine stress echocardiography (DSE) and myocardial contrast echocardiography (MCE) can predict recovery of left ventricular function after myocardial infarction. DSE also has been shown to predict left ventricular functional recovery after revascularization in chronic ischemic heart disease, whereas MCE has not been evaluated in such patients. This study was performed to compare DSE and MCE in the prediction of left ventricular functional recovery after revascularization in patients with chronic ischemic heart disease. METHODS AND RESULTS: MCE and DSE were performed in 35 patients with chronic coronary artery disease and significant wall motion abnormalities (mean ejection fraction, 0.36 +/- 0.09). Regional wall motion was scored by use of a 16-segment model wherein 1 = normal or hyperkinetic, 2 = hypokinetic, 3 = akinetic, and 4 = dyskinetic. Each segment was evaluated for contractile reserve by DSE and perfusion by MCE. Revascularization (coronary artery bypass graft [n = 13] and percutaneous transluminal coronary angioplasty [n = 10]) was successful in 23 patients. Follow-up echocardiograms were done to assess wall motion 30 to 60 days later. In 238 segments with resting wall motion abnormalities, perfusion was more likely to present than contractile reserve (97% versus 91%, P < .02). Revascularization resulted in functional recovery in 77 of 95 hypokinetic segments (81%) but only 18 of 57 akinetic segments (32%, P < .0001). DSE and MCE were not significantly different in predicting functional recovery of hypokinetic segments. In akinetic segments, DSE and MCE had similar sensitivities (89% versus 94%, respectively) and negative predictive values (93% and 97%, respectively) in predicting functional recovery. However, DSE had a higher specificity (92% versus 67%, P < .02) and positive predictive value (85% versus 55%, P < .02) than MCE in predicting functional recovery. CONCLUSIONS: Both contractile reserve by DSE and perfusion by MCE are predictive of functional recovery in hypokinetic segments after coronary revascularization in patients with chronic coronary revascularization in patients with chronic coronary artery disease. In akinetic segments, myocardial perfusion by MCE may exist in segments that do not recover contractile function after revascularization. Thus, contractile reserve during low-dose dobutamine infusion is a better predictor of functional recovery after revascularization in akinetic segments than perfusion.