Deep learning to detect significant coronary artery disease from plain chest radiographs

Background

Coronary artery disease (CAD) is the single leading cause of mortality, premature death, and morbidity worldwide. Artificial intelligence (AI) could help identify markers present within first-line diagnostic imaging routinely performed in patients referred for suspected angina, such as chest radiographs.

Purpose

To train, test, and validate a deep learning (DL) algorithm for detecting the presence of significant CAD based on chest radiographs.

Methods

Data of patients undergoing chest radiography and coronary angiography were retrospectively analysed. A deep convolutional neural network (DCNN) was designed to detect significant CAD from the patient posteroanterior/anteroposterior chest radiograph. The DCNN was trained for binary classification of severe CAD absence/presence (at least one diseased coronary vessel with ≥70% stenosis). Coronary angiography reports were used as the ground truth. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of the DCNN were calculated. Multivariate analysis was performed to identify independent correlation among the presence of significant CAD (dependent variable), DCNN prediction, and CAD risk factors.

Results

Information of 7728 patients referred for suspected angina was reviewed. Severe CAD was present in 4482 patients (58%; 1% left main, 28% one vessel, 16% two vessels, and 12% 3 vessels). Patients were randomly divided for training (70%; n=5454) and fine-tuning/testing (10%; n=773) of the algorithm. Internal validation was performed with the remaining patients (20%; n=1501). At binary logistic regression, the DCNN prediction was the strongest independent determinant of severe CAD (p<0.0001; OR: 52.8; CI: 25.1–110.9). Age (p=0.008; OR: 1.01; CI: 1.0–1.02) and Diamond-Forrester score (p<0.0001; OR: 1.022; CI: 1.018–1.026) were also independently related to CAD, although with lower significance and odds-ratios. Using an operating cut-point with high sensitivity, the DCNN had a sensitivity of 0.90 and specificity of 0.31 to detect significant CAD in the internal validation group (AUC 0.73; 95% CI DeLong, 0.69–0.76). Adding to the AI chest radiograph interpretation, patient age and angina status improved the prediction (AUC 0.77; 95% CI DeLong, 0.74–0.80).

Conclusion

The chest radiograph is ubiquitous and carries a plethora of information concerning the patient's health status, including direct and indirect signs of CAD. Our DL algorithm can predict, with high sensitivity, the presence of severe CAD in patients referred for suspected angina. It could be used to pre-test significant CAD probability in outpatient clinics, emergency room settings, and CAD screening in more extensive settings. Further studies are required to externally validate the algorithm and develop a clinically applicable tool.

Funding Acknowledgement

Type of funding sources: None.

Concomitant surgical ablation of atrial fibrillation: long-term outcomes

Introduction

Atrial fibrillation (AF) is the most common cardiac related arrhythmia, independently associated with an increased risk of death and high level of morbidity, such as stroke, heart failure, as well as frequent hospitalization and reduced quality of life. Surgical ablation is an effective therapy for patients with AF undergoing concomitant cardiac surgery.

Purpose

In this study we report the results of concomitant surgical AF ablation, in terms of efficacy and safety, with a long-term follow-up at 10 years.

Methods

Two-hundred fourteen (214) consecutive patients (female, 45.17%) underwent from 1999 to 2016 surgical ablation of AF concomitantly with other major cardiac procedures. Mean age was 67.4±9.82. Patients had persistent and long-standing persistent AF in 64.65% of cases. Primary endpoints were overall survival, freedom from stroke and freedom from AF.

Results

Perioperative mortality was 2.3% (5/214). Mean EuroSCORE II was 5.2±4.4. Concomitant mitral valve surgery was performed in 56.74% of patients, 31% of patients had a concomitant aortic valve surgery, while myocardial revascularization either isolated or associated with aortic valve was performed in 11.63% and 3.72% of cases respectively. Ablation was carried out by means radio-frequency box lesions set in 35.51% (76/214) of patients while pulmonary veins isolation with bipolar clamp and Cox-MAZE IV was performed in 51.86% (111/214) and 12.61% (27/214) of patients respectively. Left atrial appendage (LAA) exclusion was performed in 57 patients (26.51%) after careful echocardiographic investigation of diastolic and atrial function. Incidence of early postoperative (30 days) permanent pacemaker implantation was as low as 2.3%. The mean follow-up was 6.71±4.47 years. The New York Heart Association functional class (2.84 vs. 1.91, p<0.001) and ejection fraction (54.4% vs. 56.6%, p<0.001) were improved compared with the preoperative status. At 10 years Kaplan-Meier overall survival was 62.3%. Freedom from cardiac related death was 98%, while freedom from stroke was 98% at 10 years. Efficacy endpoint showed a freedom from AF at 10 years, according to HRS criteria of 66.7%. Fisher exact test comparing mitral surgery patients or ischemic CABG-patients showed no differences in terms of stroke rate (p=0.999), while postoperatively, there was a higher rate of stroke at thirty days in patients with postoperative AF (p=0.019).

Conclusions

Concomitant surgical ablation of AF was associated with a very low incidence of postoperative PM implantation and provides excellent results in terms of stable rhythm outcome at long-term. Postoperative AF significantly increased the risk of stroke in the early postoperative period.

Funding Acknowledgement

Type of funding source: None

What Does The Blanking Period Blank?

In the management of paroxysmal, drug-refractory atrial fibrillation, pulmonary vein isolation has become a widely accepted treatment option. Currently, the arrhythmias following any form of myocardial ablation are not considered within a period of three months, known as "the blanking period". Although this period is authority- rather than evidence-based, it has become universally recognized. Indeed, several mechanisms play a role to determine the transient increased risk of post-procedural atrial tachyarrhythmias, occurring early after the procedure. Acute inflammatory changes may be responsible for immediate recurrence, since application of ablative energy on atrial tissue has a pro-inflammatory- and potentially arrhythmogenic effect. Atrial arrhythmias within the first 3 months after ablation are very common (35% to 65% of cases) and their significance as predictor of late recurrences is more significant during the first month. Furthermore, the current biological evidences indicate that the edema of the surrounding and ablated tissue is no longer present after 1 month. In our letter we advocate the reasons why a blanking period of four weeks should appear more reasonable, fostering its clinical importance and utility.

The pivotal role of echocardiography in the assessment of multivalvular heart disease

Multivalvular heart disease (MHD) accounts for approximately 15% of the patients undergoing valve surgery in the EuroHeart Survey and for 8.6% of all valvular surgical interventions. Most clinical studies on valvular heart disease are focused on single-valve disease and very few data stress the difficulties encountered in the diagnostic assessment and clinical decision making of multiple defects, also concerning the reciprocal hemodynamic influence or the overlap of surgical indications. Many fields related to multiple valve disease are not encountered in the European Guidelines on Valvular Heart Disease (ESC) or the American College of Cardiology/American Heart Association (ACC/AHA). Increasing age and new trends of mixed population have newly aroused interest in multivalvular heart disease in the developed countries, still in need of new clinical insights. According to the high comorbidities of candidates, the appropriate diagnostic framework necessary for the correct diagnosis and best clinical outcome may still be challenging. The paper reviews multivalvular heart disease (except congenital heart disease) from aetiology and background definition to surgical outcome, with special emphasis on echocardiographic assessment and clinical interpretation.

A simplified technique for antegrade selective cerebral perfusion

Various methods of cerebral protection have been used during aortic arch surgery. We reviewed our experience with a modified technique for selective cerebral perfusion (SCP) administration during surgery on the thoracic aorta from October 1999. Conventionally, this technique requires an additional roller pump on the cardiopulmonary bypass (CPB) console. In order to simplify the extracorporeal circuit (ECC), the paediatric double-roller pump used for the administration of cardioplegia was utilized by adding a 'Y-connection' on the blood line of the cardioplegia circuit, upstream of the cardioplegia reservoir, to provide SCP blood flow. SCP administration with a Y-connection is both easy and fast to set up on the ECC circuit and does not create additional difficulties to the surgeon. It simplifies SCP delivery by allowing the perfusionist to use a standard ECC system set-up.

Atrial electroanatomic remodeling after circumferential radiofrequency pulmonary vein ablation: efficacy of an anatomic approach in a large cohort of patients with atrial fibrillation

BACKGROUND

Circumferential radiofrequency ablation around pulmonary vein (PV) ostia has recently been described as a new anatomic approach for atrial fibrillation (AF).

METHODS AND RESULTS

We treated 251 consecutive patients with paroxysmal (n=179) or permanent (n=72) AF. Circular PV lesions were deployed transseptally during sinus rhythm (n=124) or AF (n=127) using 3D electroanatomic guidance. Procedures lasted 148+/-26 minutes. Among 980 lesions surrounding individual PVs (n=956) or 2 ipsilateral veins with close openings or common ostium (n=24), 75% were defined as complete by a bipolar electrogram amplitude <0.1 mV inside the lesion and a delay >30 ms across the line. The amount of low-voltage encircled area was 3594+/-449 mm(2), which accounted for 23+/-9% of the total left atrial (LA) map surface. Major complications (cardiac tamponade) occurred in 2 patients (0.8%). No PV stenoses were detected by transesophageal echocardiography. After 10.4+/-4.5 months, 152 patients with paroxysmal AF (85%) and 49 with permanent AF (68%) were AF-free. Patients with and without AF recurrence did not differ in age, AF duration, prevalence of heart disease, or ejection fraction, but the LA diameter was significantly higher (P<0.001) in permanent AF patients with recurrence. The proportion of PVs with complete lesions was similar between patients with and without recurrence, but the latter had larger low-voltage encircled areas after radiofrequency (expressed as percent of LA surface area; P<0.001).

CONCLUSIONS

Circumferential PV ablation is a safe and effective treatment for AF. Its success is likely due to both PV trigger isolation and electroanatomic remodeling of the area encompassing the PV ostia.

Activation of coagulation and fibrinolysis during coronary surgery: on-pump versus off-pump techniques

BACKGROUND

The authors studied the changes in selected hemostatic variables in patients undergoing coronary surgery with on-pump coronary artery bypass grafting (CABG) or off-pump coronary artery bypass surgery (OPCAB) techniques.

METHODS

Platelet counts and plasma concentrations of antithrombin, fibrinogen, D dimer, alpha(2) antiplasmin, and plasminogen were measured preoperatively, 5 min after administration of heparin, 10 min after arrival in the intensive care unit, and 24 h after surgery in patients scheduled to undergo OPCAB (n = 15) or CABG (n = 15). To correct for dilution, hemostatic variables and platelet counts were adjusted for the changes in immunoglobulin G plasma concentrations and hematocrit, respectively.

RESULTS

Adjusting for dilution, antithrombin and fibrinogen concentrations decreased to a similar extent in patients undergoing OPCAB or CABG (pooled means and 95% confidence limits of the mean: 95.5% of baseline, 93-98%, P = 0.002, and 91.7% of baseline, 88-95%, P = 0.0001), respectively, whereas alpha(2)-antiplasmin concentrations were unchanged. Only CABG was associated with a reduction in platelet counts (76% of baseline, 66-85%, P = 0.0001), plasminogen concentrations (96% of baseline, 91-99%, P = 0.011), and increased D-dimer formation (476%, 309-741%, P = 0.004). Twenty-four hours after surgery, platelet counts were still lower in patients undergoing CABG (P = 0.049), but all the investigated variables adjusted for dilution were similar in the two groups.

CONCLUSIONS

Coronary surgery causes a net consumption of antithrombin and fibrinogen. A transient decrease in platelet counts, with plasminogen activation and increased D-dimer formation, however, is only observed with CABG. Twenty-four hours after surgery, the hemostatic profiles of patients in both groups are similar.

Tranexamic acid in off-pump coronary surgery: a preliminary, randomized, double-blind, placebo-controlled study

BACKGROUND

We evaluated the hemostatic effects of tranexamic acid, a synthetic antifibrinolytic drug, in patients undergoing beating-heart coronary surgery.

METHODS

Forty consecutive patients were in a double-blind manner, prospectively randomized into two groups: 20 patients received tranexamic acid (bolus of 1 g before skin incision, followed by continuous infusion of 400 mg/hr during surgery), and 20 patients received saline. As primary outcomes, bleeding and allogeneic transfusions were considered. D-dimer and fibrinogen plasma levels were also evaluated to monitor the activation of fibrinolysis. Major postoperative thrombotic events, as a potential consequence of antifibrinolytic treatment, were recorded.

RESULTS

The treatment group had significantly lower postoperative bleeding (median [25th to 75th percentiles]: 400 mL [337 to 490 mL] vs 650 ml [550 to 862 mL], p < 0.0001), lower need for allogeneic blood products (1,200 vs 5,300 mL, p < 0.001), and lower postoperative D-dimer plasma levels. No postoperative thrombotic complications were observed in either group.

CONCLUSIONS

In this initial series of patients undergoing off-pump coronary surgery, tranexamic acid appears to be effective in reducing postoperative bleeding and the need for allogeneic blood products.

[Epicardial ablation of atrial fibrillation during heart valve surgery]

BACKGROUND

We report the results of an intraoperative ablation procedure for combined treatment of atrial fibrillation (AF) in patients affected by heart valve disease.

METHODS

From February 1998 to June 2000, 80 patients scheduled for heart valve operations underwent combined surgical treatment of AF. Seventy-eight patients had mitral valve disease and 2 had aortic regurgitation; 74 patients were affected by chronic AF (mean 50 +/- 74 months, range 6-480 months) and 6 had paroxysmal AF. A left atrial set of radiofrequency ablations (mainly epicardial) was performed in all patients.

RESULTS

Thirty-five patients underwent conservative mitral valve surgery, 43 had mitral valve replacement and 2 had aortic valve replacement. The combination of the ablation procedure did not lead to a substantial prolongation of cardiopulmonary and aortic cross clamp time and did not increase perioperative morbidity. No procedure-related complications were recorded. Operative mortality was favorably comparable with that of valvular surgery alone (2.5%). Mean hospital stay was 6.8 +/- 4.4 days. At follow-up (16.2 +/- 9.2 months, range 3-28 months), 61 patients (78.2%) were in stable sinus rhythm; all of them recovered left and right atrial contractility as assessed by Doppler echocardiography.

CONCLUSIONS

The combined treatment of AF with a radiofrequency ablation surgical technique is effective in restoring stable sinus rhythm and atrial contractility. The procedure is low risk thereby allowing a prompt clinical recovery after operation. It should therefore be considered in all patients with AF undergoing open-heart surgery.

Tranexamic acid administration after cardiac surgery: a prospective, randomized, double-blind, placebo-controlled study

BACKGROUND

Many different doses and administration schemes have been proposed for the use of the antifibrinolytic drug tranexamic acid during cardiac surgery. This study evaluated the effects of the treatment using tranexamic acid during the intraoperative period only and compared the results with the effects of the treatment continued into the postoperative period.

METHODS

Patients undergoing elective cardiac surgery with use of cardiopulmonary bypass (N = 510) were treated intraoperatively with tranexamic acid and then were randomized in a double-blind fashion to one of three postoperative treatment groups: group A: 169 patients, infusion of saline for 12 h; group B: 171 patients, infusion of tranexamic acid, 1 mg x kg(-1) x h(-1) for 12 h; group C: 170 patients, infusion of tranexamic acid, 2 mg x kg(-1) x h(-1) for 12 h. Bleeding was considered to be a primary outcome variable. Hematologic data, allogeneic transfusions, thrombotic complications, intubation time, and intensive care unit and hospital stay duration also were evaluated.

RESULTS

No differences were found among groups regarding postoperative bleeding and outcomes; however, the group treated with 1 mg x kg(-1) x h(-1) tranexamic acid required more units of packed red blood cells because of a significantly lower basal value of hematocrit, as shown by multivariate analysis.

CONCLUSIONS

Prolongation of treatment with tranexamic acid after cardiac surgery is not advantageous with respect to intraoperative administration alone in reducing bleeding and number of allogeneic transfusions. Although the prevalence of postoperative complications was similar among groups, there is an increased risk of procoagulant response because of antifibrinolytic treatment. Therefore, the use of tranexamic acid during the postoperative period should be limited to patients with excessive bleeding as a result of primary fibrinolysis.

Mitral valve surgery with concomitant treatment of atrial fibrillation

Recovery of sinus rhythm after mitral valve surgery in patients with chronic atrial fibrillation lowers thromboembolic risk and improves survival and quality of life. This article reviews the principal surgical procedures devised in the 1980s and 1990s to treat atrial fibrillation during mitral valve operations. Advantages and drawbacks of the different techniques are discussed. Traditional atrial fibrillation surgery is technically demanding and increases operative morbidity. Simplified techniques, mostly limited to the left atrium, have been developed to reduce operation time and procedure-related complications. Intraoperative radiofrequency ablation has recently proven extremely effective in atrial fibrillation surgery, allowing a further simplification of the procedures. We report the results of an original technique for atrial fibrillation treatment during mitral valve surgery through epicardial radiofrequency ablation. Based on recently reported results of atrial fibrillation surgery and on prognostic considerations, specific treatment of both chronic and paroxysmal atrial fibrillation is indicated in virtually all affected patients undergoing mitral valve surgery.

Tranexamic acid compared with high-dose aprotinin in primary elective heart operations: effects on perioperative bleeding and allogeneic transfusions

OBJECTIVE

Since excessive fibrinolysis during cardiac surgery is frequently associated with abnormal perioperative bleeding, many authors have advocated prophylactic use of antifibrinolytic drugs to prevent hemorrhagic disorders. We compared the effects of tranexamic acid (a synthetic antifibrinolytic drug) with aprotinin (a natural derivative product with antifibrinolytic properties) on perioperative bleeding and the need for allogeneic transfusions.

METHODS

In a single-center prospective randomized unblinded trial, 1040 consecutive patients undergoing primary, elective cardiac operations with cardiopulmonary bypass received either high-dose aprotinin or tranexamic acid. The aprotinin group (518 patients) received 280 mg in 20 minutes before the skin incision, 280 mg in the priming solution of the extracorporeal circuit, and a continuous infusion of 70 mg/h throughout the operation. The tranexamic acid group (522 patients) received 1 g in 20 minutes before the skin incision, 500 mg in the priming solution of the extracorporeal circuit, and a continuous infusion of 400 mg/h during the operation. Postoperative bleeding, perioperative transfusions, and hematologic variables were evaluated at fixed times. Postoperative thrombotic complications, intubation time, intensive care unit stay, and hospital stay were recorded.

RESULTS

Postoperative bleeding was similar in the 2 groups: aprotinin 250 mL (150-400 mL) versus tranexamic acid 300 mL (200-450 mL) (median and 25th-75th quartiles), median difference of 50 mL (95% confidence intervals, 0-50 mL). The number of transfusions and the outcome did not differ.

CONCLUSIONS

Tranexamic acid and aprotinin show similar clinical effects on bleeding and allogeneic transfusion in patients undergoing primary elective heart operations. Since tranexamic acid is about 100 times cheaper than aprotinin, its use is preferable in this type of patient.

A simple way to treat chronic atrial fibrillation during mitral valve surgery: the epicardial radiofrequency approach

OBJECTIVE

We describe an original radiofrequency ablation technique to treat chronic atrial fibrillation in patients undergoing mitral valve surgery. Most of the procedure is carried out epicardially, in order to avoid an undue increase of surgical time and trauma.

METHODS

The ablations are performed using a temperature-controlled multipolar radiofrequency catheter. Two encircling lesions around the ostia of the right and of the left pulmonary veins are carried out epicardially, usually before cardiopulmonary bypass. Through a conventional left atriotomy the ablation procedure is completed with two endocardial lesions connecting the two encirclings between them and to the mitral valve annulus. After the mitral valve procedure is performed, the left appendage is sutured.

RESULTS

From February 1998 to May 1999, 40 patients with chronic atrial fibrillation (43. 1+/-51.9 months) underwent combined radiofrequency ablation and mitral valve surgery. Mean left atrial diameter was 56.8+/-10.7 mm. Mean cardiopulmonary bypass and aortic cross-clamp time were, respectively, 119.1+/-26.3 and 76.7+/-21.0 min. Mean postoperative blood loss was 287.2+/-186.6 ml. No reexploration for bleeding occurred. One patient died of pneumonia 12 days after operation. No patient needed permanent pacemaker implantation. Mean postoperative hospital stay was 7.3+/-5.6 days. At follow-up (mean 11.6+/-4.7 months), 30/39 (76.9%) of the patients were in stable sinus rhythm. All patients in sinus rhythm 3 months after operation recovered both left and right atrial contractility at echocardiographic control (mean 7.3+/-3.4 months). The left atrial diameter decreased significantly in patients recovering sinus rhythm.

CONCLUSIONS

Epicardial radiofrequency ablation is a safe means to achieve surgical ablation of atrial fibrillation with a high success rate. The simplicity of the technique and the low procedure-related risk should dictate combined treatment virtually in all patients with atrial fibrillation undergoing open heart operations.

Primary cardiac sarcoma in pregnancy: a case report and review of the literature

Primary cardiac sarcoma (PCS) is a rare disease with a poor prognosis, because of diagnostic delay, therapeutic difficulties, and high metastatic potential. Surgery is the standard treatment. A case of PCS in pregnancy is reported, with a review of published surgical series of PCSs, focusing on the role of surgery and adjuvant therapy. Prompt surgery improved cardiac function and patients' outcome in comparison with untreated cases. The role of adjuvant treatment was analyzed only in a few series, mainly without distinction between postoperative chemotherapy and radiotherapy; adjuvant therapy improved survival in the larger series of resected PCSs. Only three other cases of PCS in pregnancy were reported. In the present case, resection was performed with no major complication for the mother and the infant. Even if the patient's survival was short, cardiac surgery allowed prolonging of pregnancy until an acceptable possibility of fetal survival was reached. Although resection is not curative in most cases, surgery remains the treatment of choice for PCS and has a definite palliative significance. The role of postoperative chemotherapy and radiotherapy is difficult to ascertain; however, adjuvant chemotherapy seems advisable in high-grade tumors.

Inferior epigastric artery as a conduit for myocardial revascularization: a two-year clinical and angiographic follow-up

The inferior epigastric artery has been proposed as a suitable conduit for myocardial revascularization but its mid-term patency rate has not been assessed. A prospective clinical and angiographic study on the use of the inferior epigastric artery as an additional arterial conduit together with bilateral internal thoracic artery grafting was conducted in 38 patients. No deaths or major postoperative complications occurred. Twenty-three patients underwent repeat angiography after an average of 21.2 months. The left and right internal thoracic artery grafts patency rate was 95.6% (44/46), while inferior epigastric artery patency rate was 52.2% (12/23). By relating patency to the grafted coronary branch, the following results were obtained: 100% for the left anterior descending (3/3), right coronary (1/1) and ramus medianus (1/1); 40% (4/10) and 37.5% (3/8) for diagonals and obtuse marginals respectively. The low patency rates observed when the inferior epigastric artery is used on diagonals and obtuse marginals indicate that this vessel cannot be considered a suitable conduit for extensive application of arterial revascularization. We suggest that the inferior epigastric artery should only be used in patients presenting with contraindications to bilateral internal thoracic artery or right gastroepiploic artery grafting, or exhibiting unsuitable saphenous veins.

Timing for surgical treatment in native infective endocarditis. A seven-year experience

BACKGROUND

Early surgical intervention in infective endocarditis is performed only when there is persistence of sepsis, hemodynamic instability or when arterial embolism has occurred, otherwise a 4-week antibiotic therapy before surgery is considered necessary. Our 7-year experience in the surgical treatment of native endocarditis in 28 patients, is here revised focusing on the timing of surgery.

METHODS

Patients were retrospectively divided into group A (n. 16) with blood cultures that became negative before surgery and group B (n. 11) with blood cultures positive at the time of urgent surgery. One patient with constantly negative blood cultures was not assigned to any group. In group A antibiotic therapy was administered until 3 consecutive blood cultures became negative and the patients were then operated on the basis of echocardiographic findings after a mean duration of antibiotic therapy of 17.4 +/- 6.3 days.

RESULTS

Twenty-six patients out of 28 underwent replacement of the infected valve (mechanical bileaflets in 16 patients, porcine stented in 7 and porcine stentless in 3). Valve repair was performed in 2 patients. Overall operative mortality was) 7.1% (2/28); death occurred in 2 patients of group B, operated on for cardiogenic shock. Two/26 patients died (1 acute renal failure and 1 stroke) at a mean follow-up of 32.5 +/- 24.8 (range 3-95) months.

CONCLUSIONS

Patients who underwent surgery for infective endocarditis after blood culture negativization showed no mortality and no recurrence of disease even if a 4 weeks antibiotic course was not completed. This experience suggests that earlier operations can be performed safely, lowering the incidence of hemodynamic impairment and arterial embolism.

[Transmyocardial laser revascularization in patients with peripheral coronary atherosclerosis. Indications and preliminary results]

BACKGROUND

Surgical intervention for coronary artery disease (CAD) is determined by the viability of coronary artery branches. When peripheral coronary artery disease is present, conventional bypass grafting is not suitable. Research has recently been done on alternative methods such as transmyocardial laser revascularization (TMLR). TMLR works through the vascular connections that are present between the cardiac chambers and the myocardial muscle in the human heart. The creation of 1-mm transmural cardiotomies through a CO2 laser should improve myocardial perfusion.

METHODS

From February to June of 1996, twelve patients (9 males and 3 females with a mean age of 67.8 +/- 4.6) with CAD (mean n0 of diseased vessels 2.7), angina (mean CCS class 3.5 +/- 0.5), mean ejection fraction 47.8% and viable ischemic myocardium on scintiscan in segments without graftable coronary branches, underwent TMLR at our institute. Nine of the 12 patients also underwent associated CABG (mean number of anastomoses per patient: 2.5). Cardiopulmonary bypass was never used, since coronary anastomoses and laser cardiotomies were performed on the beating heart.

RESULTS

Perioperative mortality was 2/12 (16.6%). Postoperative inotropic support and diuretic therapy was required in most cases. At a mean follow-up period of 4.2 months, all remaining patients are still alive: 5/10 are angina-free (CCS 0), 4/10 are in CCS class 1 and 1/10 is in CCS class 2 (mean 0.6 +/- 0.7).

CONCLUSIONS

We believe that TMLR could be considered an effective mean to treat symptomatic myocardial ischemic disease in which coronary bypass grafting is not suitable. During the immediate postoperative period, contractile myocardial dysfunction occurs in a high percentage of patients treated using TMLR and consequently it would be worthwhile to invest in further research.

Six-and-half years' experience with the St. Jude BioImplant porcine prosthesis

BACKGROUND AND AIMS OF THE STUDY

In this study, we reviewed our experience in heart valve replacement with the St. Jude BioImplant heart valve, which is a low-profile, low-pressure glutaraldehyde-fixed porcine prosthesis mounted on a flexible Delrin stent.

METHODS

During the period May 1989-January 1996, 117 patients were implanted with 132 BioImplant prostheses; three patients were lost to follow up and excluded from the series. Mean age was 67.5 +/- 9.8 years (range: 19 to 82 years); myocardial revascularization was performed in 22 (19.3%) patients. In-hospital mortality rate was 6% (7/117 patients). By January 1996, 114 patients (53 males, 61 females), in whom 59 aortic, 35 mitral, 15 mitro-aortic and five tricuspid prostheses had been implanted, were eligible for the analysis. Mean follow up was 40.4 +/- 21.7 months (range: 1 to 76 months).

RESULTS

The survival probability of survivors was 72.1 +/- 6.5 at 77 months. Seventeen patients died during follow-up. The mean NYHA class improved from 3.1 +/- 0.6 preoperatively to 1.4 +/- 0.6 postoperatively. The freedom probabilities were respectively 89.5 +/- 5.3% from thromboembolism, 93.2 +/- 3.7% from infective endocarditis, 84.5 +/- 10.3% from structural dysfunction, 99.1 +/- 0.9% from non-structural dysfunction, and 80.1 +/- 10.2% from reoperation. The freedom probability for valve-related events was respectively 75.3 +/- 12.3%, 98.0 +/- 1.9% and 67.2 +/- 17.2% for patients who underwent mitral, aortic and mitro-aortic heart valve replacement (p = 0.05 comparing only patients who underwent mitral or aortic replacement); moreover the freedom probability from valve-related events was 71.6 +/- 11.2% in patients aged < or = 65 years and 90.2 +/- 6.6% in patients aged > 65 years (p = 0.006).

CONCLUSIONS

The BioImplant heart valve, in our experience, seems to be a valuable device which shows a mid-term performance similar to that of other porcine prostheses.

Surgical treatment for life-threatening acute myocardial infarction: a prospective protocol

OBJECTIVE

In this paper we describe the preliminary results of a prospective operative protocol designed in order to define the role of emergent myocardial revascularization in extensive acute myocardial infarction and in post-infarction cardiogenic shock.

METHODS

Entry criteria are: age < 75 years; anterior acute myocardial infarction with ST segment elevation > 4 leads, infero-postero-lateral or inferior and right ventricular within 6 h from onset of chest pain; post-infarction cardiogenic shock within 3 h from onset of shock. From November 1994 to July 1995, after emergency coronary arteriography, 23 patients were treated by coronary artery bypass grafting. Fifteen were operated for extensive acute myocardial infarction (group A, mean age 54.1 +/- 9.4 years) and eight for post-infarction cardiogenic shock (group B mean age 65.0 +/- 8.7 years). Mean time from onset was 4.4 +/- 1.3 h in group A and 2.2 +/- 0.8 h in group B. Mean left ventricular ejection fraction was 39.3 +/- 12.7% in group A and 22.6 +/- 3.5% in group B. Six out of eight group B patients needed intraaortic balloon counterpulsation preoperatively, and 2/8 cardiopulmonary resuscitation.

RESULTS

Myocardial revascularization consisted in 3.4 +/- 1.1 grafts in group A (vein grafts, except for 8 patients who also received a left internal thoracic artery graft) and 3.3 +/- 1.1 vein grafts in group B. All patients in group B and 3/15 (20%) in group A underwent intraaortic balloon counterpulsation. In-hospital death occurred in 1/15 (6.7%) patients of group A and in 4/8 (50%) patients of group B. At a mean follow-up of 4.1 +/- 3.4 months for group A and 3.9 +/- 2.2 months for group B left ventricular ejection fraction was 43.4 +/- 9.0% in group A and 35.7 +/- 13.1% in group B.

CONCLUSIONS

Experience of 9 months with this prospective protocol showed its effectiveness in the management of critically ill patients with acute coronary occlusion leading to low mortality rate in acute myocardial infarction and improved survival rate in post-infarction cardiogenic shock.

[Emergency surgical revascularization in acute myocardial infarct. The preliminary results of a prospective study]

In this paper we describe 1-year experience with a perspective operative protocol of emergency myocardial revascularization in extensive acute myocardial infarction (AMI). Entry criteria were: age < 75 years; anterior AMI with ST segment elevation > 4 leads, infero-postero-lateral or inferior and right ventricular AMI, within 6 hours from symptom onset. After coronary arteriography, an emergency staff, composed by cardiologists and cardiac surgeons, addresses the patients to coronary artery bypass grafting (CABG) or to percutaneous transluminal coronary angioplasty (PTCA). From November 1994 to November 1995, 35 patients were enrolled: 19 (mean age 54.3 +/- 9.7 years) underwent CABG and 16 were treated with PTCA. Myocardial protection was such as to restore energetic substrates and to prevent reperfusion injury: surgical technique consisted of antegrade-retrograde substrate-enriched blood cardioplegic solution delivery, early cardioplegic delivery on the infarcting area via a saphenous graft, retrograde controlled reperfusion before aortic unclamping and then prolonged reperfusion of the infarcted myocardium. In 8 patients (mean age 50.9 +/- 8.6 years), with anterior AMI and stable hemodynamics, a left internal thoracic artery graft was used, performing the prolonged controlled reperfusion retrogradely before aortic unclamping. In hospital death occurred in 1/19 (5.3%) patients because of cerebral hemorrhage. At a mean follow-up of 5.1 +/- 3.7 months 17 patients (94.4%) were in NYHA functional class I-II and 1 patient (5.6%) complained of effort angina, that was well controlled with medical therapy. Left ventricular ejection fraction calculated by echocardiography preoperatively, before discharge and at follow-up was respectively 39.3 +/- 12.7, 43.1 +/- 8.9 and 43.4 +/- 9.0%. In the last 8 consecutive patients thermodilution and transesophageal echocardiography monitoring were performed preoperatively and 12 hours after CABG: in all cases ejection fraction and cardiac index increased after CABG, from 42.2 +/- 13.5 to 48.6 +/- 14.3% (p = 0.01) and from 2.8 +/- 0.5 to 3.4 +/- 0.6 l/min/m2 (p = 0.005), respectively. The preliminary results show the effectiveness of this perspective protocol in the management of critically ill patients with extensive AMI.

Advantages of delayed sternal closure in cardiac-compromised adult patients

Severe hemodynamic dysfunction may follow closure of the median sternotomy in patients with myocardial edema, cardiac dilatation, postcardiotomy shock, or raised end-expiratory alveolar pressure. Open sternotomy and delayed sternal closure (DSC) is a well described adjunct in complicated cardiac operations, which is more widely applied in neonates. In this article we report our results in using open sternotomy in eight adult patients from January 1994 to February 1995 (excluding patients who needed ventricular assistance devices [VADs]). Three patients died in hospital: 1 case of multiorgan failure; 1 cases of refractory low cardiac output syndrome; and 1 case of respiratory distress syndrome. Our experience confirms that DSC is an effective means of dealing with postoperative hemodynamic impairment. Furthermore, this technique may represent an intermediate step between intraaortic balloon counterpulsation and VADs and should be given a role in the prophylaxis of low postoperative cardiac output and multiorgan failure, particularly when contraindications to VAD exist.

Myocardial revascularization with bilateral internal thoracic artery in patients with left main disease or left ventricular dysfunction: an incremental risk?

Although long-term patency of the internal thoracic artery (ITA) is well stated, there is still some concern about its perioperative performance. We considered 122 consecutive patients, 63 with left main disease (LMD; mean age 60 years) and 59 with left ventricular dysfunction (LVD; mean age 59 years) who underwent coronary artery bypass grafting in our Institute from March 1988 to September 1992. Patients with LMD were divided into 2 groups: LMD I: 29 patients receiving only ITA grafts on the left coronary system and LMD II: 34 patients having a single ITA graft on the left coronary system. Patients with LVD were divided into: LVD I: 44 patients operated with bilateral ITA and LVD II: 15 patients receiving a single ITA graft. Perioperative complications in LMD I and LMD II patients were respectively: myocardial necrosis in 2 (6.9%) versus 3 (8.8%), use of intra-aortic balloon pump (IABP) in 2 (6.9%) versus 2 (5.9%); no death occurred in both groups. Perioperative results in groups LVD I and LVD II were: death in 1 patient (2.2%) versus 1 (6.7%), myocardial necrosis in 2 (4.5%) versus 1 (6.7%) and IABP in 4 (9.1%) versus 2 (13.3%). In our experience the use of bilateral ITA grafts in patients with LMD and LVD was not related to an incremental risk. We conclude that LMD and LVD should not be considered as contraindications to the extensive use of arterial conduits.

Total arterial myocardial revascularization

The superiority of the internal thoracic artery (ITA) compared with venous conduits in terms of late graft patency is nowadays well documented. The inferior epigastric artery (IEA) was recently proposed as an alternative conduit for coronary artery surgery with good early clinical and angiographic results. To improve the benefits from myocardial revascularization, we expanded the use of these arterial conduits. From June 1988 to December 1991, 615 patients underwent coronary surgery in our institute. In 138 of them (22.4%) we performed total arterial myocardial revascularization placing 2 or more coronary anastomoses. An average of 2.37 anastomoses per patient were placed with the maximum number of 6 in one case. Only one patient died of cardiac related causes (0.72%). Perioperative morbidity included myocardial infarction and sternal dehiscence in 5 patients each (3.6%). No stroke or reoperation for bleeding occurred. No rectus muscle necrosis was recorded. Accurate preoperative planning of graft placement allows for the performance of as many as 6 distal anastomoses using bilateral ITA and single IEA grafts only, thus completely revascularizing most of the hearts with three-vessel disease. In our series this procedure was not reflected in an increase in the perioperative morbidity. We choose an elective total arterial revascularization in younger (under 65 years) patients who, while showing a lower incidence of complications in our study, are likely to derive the highest benefits from the good durability of ITA and hopefully IEA grafts.

[Current role of lymphography in the study of systemic lymphatic diseases]

The usefulness and reliability of lymphography for staging purposes in Hodgkin's disease are discussed with reference to a personal series.