Minimally invasive heart surgery.
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Biomedical subjects
Publications and source records attributed to A M Calafiore.
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BACKGROUND: Partial harvesting of the left internal mammary artery (LIMA) is a widespread technique used during minimally invasive coronary operations performed through a left anterior small thoracotomy. The influence of persisting LIMA branches was investigated to evaluate their effect on the blood flow of the left anterior descending artery. METHODS: Thirty patients, 15 with totally (group A) and 15 with partially (group B) harvested LIMAs, were evaluated. All the patients underwent postoperative angiography, during which a flow map of the LIMA was performed. The average peak velocity and the diastolic-to-systolic peak velocity ratio were recorded. The LIMA graft flow pattern was recorded in the proximal and distal thirds of the artery. Intramammary adenosine (12 to 14 microg) was injected and the average peak velocities before and after injection were calculated. RESULTS: The average peak velocity was similar in both groups in the proximal and distal thirds of the LIMA (25 +/- 7 and 26 +/- 5 cm/sec, respectively, in group A versus 27 +/- 5 and 25 +/- 5 cm/sec, respectively in group B; p = NS). The diastolic-to-systolic peak velocity ratio was similar proximally (0.78 +/- 0.3 in group A versus 0.69 +/- 0.3 cm/s in group B; p = NS), but not distally (1.72 +/- 0.1 in group A versus 0.97 +/- 0.3 in group B; p < 0.0005). The LIMA graft flow reserve was similar both proximally and distally (2.6 +/- 0.6 and 2.5 +/- 0.3 cm/s, respectively, in group A versus 2.6 +/- 0.5 and 2.6 +/- 0.3 cm/s, respectively, in group B; p = NS). CONCLUSIONS: The persistence of LIMA branches does not influence the blood flow of the left anterior descending artery after acute adenosine-induced myocardial hyperemia. If a left anterior small thoracotomy is used in left anterior descending artery direct revascularization, complete LIMA harvesting is not mandatory and depends on the personal preference of the surgeon.
BACKGROUND: We reviewed our experience with left internal mammary artery (LIMA)-to-left anterior descending artery (LAD) anastomosis on a beating heart through a left anterior small thoracotomy. METHODS: This procedure was performed in 343 of 358 scheduled patients; in 15 (4.2%) the LAD was not suitable or was too small. The chest was opened in the fourth (127, 37.0%) or fifth (197, 57.4%) intercostal space, or both (19, 5.6%); the length of the harvested LIMA was 4-15 cm. The LAD was occluded by means of two 4-0 Prolene (Ethicon, Somerville, NJ) sutures, both snared on a small piece of silicone tubing. The anastomosis was performed with two 8-0 Prolene sutures. In the early postoperative period all patients underwent angiography or a doppler flow assessment of the LIMA or both. RESULTS: In 310 patients the LIMA was connected directly to the LAD; to elongate the LIMA, in 30 patients an inferior epigastric artery and in 3 patients a saphenous vein was used. In 2 patients the diagonal branch was also grafted using an inferior epigastric artery from the LIMA. Three patients (0.9%) died during the first 30 days after the operation, and 4 other patients (1.2%) died after the first month. Twenty-five patients (7.3%) were reoperated on because of anastomotic or conduit failure, 18 (5.2%) early and 7 (2.1%) late; one additional patient had a late percutaneous transluminal coronary angioplasty for anastomotic stenosis. At a mean of 9.5 +/- 5.7 months of follow-up, 336 patients (98.0%) were alive, asymptomatic with or without medical treatment, and without cardiac events. COMMENT: Left internal mammary artery-to-LAD anastomosis performed on a beating heart through a left anterior small thoracotomy is a procedure that can be performed with low risk and acceptable midterm results in selected patients.
UNLABELLED: Surgeons have traditionally relied on ring preparations to predict how arterial bypass conduits will behave in the postoperative circulation. OBJECTIVE: This study compared pharmacologic [norepinephrine (NE) challenge] and physiologic [arterial preload] responses of gastroepiploic (GEA) and internal thoracic (ITA) arteries in a standard static ring preparation and a dynamic perfusion system. METHODS: Six GEAs (1.0-1.5 mm dia.) and six ITAs (1.5-2.0 mm dia.) 11 cm long were harvested from adult pigs and mounted on a computer controlled perfusion system. Inflow pressure was set at 80 mmHg and outflow resistance was adjusted to simulate high (80-90 ml/min) and low (15-20 ml/min) flow demands. NE response (10(-9)-10(-5) M) was measured under low flow conditions and at high flow conditions when distal arterial pressure (load) was reduced. NE response (10(-9)-10(-5) M) was also evaluated in arterial rings (ITA N = 6, GEA N = 6) with tensions adjusted to simulate the loads occurring at low flow (80 mmHg) and high flow (60 mmHg) situations. RESULTS: In the static ring preparation, NE response [ED50] was similar for both GEA and ITA and was not affected by load. The dynamic preparation demonstrated that the GEAs were significantly more responsive to NE than the ITAs [ED50 high flow ITA 6.1 +/- 0.3**, GEA 7.2 +/- 0.3***; *P < 0.05 versus baseline, **P < 0.05 versus low flow values, ***P < 0.05 versus ITA]. Furthermore, in the dynamic preparation, NE response was profoundly affected by reduced load which occurs under high flow conditions [7.18 +/- 0.3 versus 6.1 +/- 0.3 under high flow and 5.8 +/- 0.1 versus no response under low flow conditions]. CONCLUSION: Static ring preparations do not discern differences between ITA and GEA susceptibility to spasm and fail to detect the effect of load. The dynamic preparation demonstrated significant differences between the GEA and ITA potential to spasm which is consistent with widespread clinical experience. Furthermore a dynamic preparation is highly sensitive to reduced load which occurs under high flow conditions. Although it is more demanding, the dynamic preparation provides superior information to the surgeon in predicting the behavior of arterial bypass grafts.
OBJECTIVE: Sometimes the left internal mammary artery (LIMA) is not long enough to reach a too lateral LAD when a left anterior small thoracotomy (LAST operation) is the surgical approach to graft the LAD. LIMA elongation with an inferior epigastric artery (IEA) can be an useful surgical option. METHODS: From November 1994 to June 30, 1996, out of 289 patients who underwent LAST operation; 28 patients had a LIMA elongation with an IEA, 20 patients had single vessel disease, 4 had two vessel disease, and 4 three vessel disease. Mean age was 62 +/- 22 (48-84) and mean EF was 57 +/- 86. The IEA was used only when the LAD was totally or nearly occluded with no transmural myocardial infarction (high expected run off). RESULTS: All patients had an uneventful recovery. After 315 +/- 104 days from surgery all were asymptomatic. A late doppler flow assessment, performed in 28 patients, showed a high velocity diastolic flow in 27. One patient was reoperated on because of graft occlusion 84 days after surgery. An angiography was performed after 87.5 +/- 23.3 days in 22 patients. All conduit and anastomoses were patent but one, (patency rate 21/22, 95.4%); another showed mild anastomotical stenosis at the LIMA-IEA junction without clinical signs (perfect patency rate 20/22, 90.9%). CONCLUSIONS: IEA elongation of LIMA is an alternative strategy to reach a lateral LAD in selected cases; a satisfying patency rate can be expected, when correct surgical indications are used.
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Left ventricular remodeling, through long-term left ventricular chamber dilation and increased wall stress can result in alteration of ventricular architecture and impairment of systolic and diastolic performance. Most of the studies regard post acute myocardial infarction remodeling, knowledge is still lacking about preoperative and postoperative factors which predict the long-term prognosis of patients who underwent venous coronary artery bypass graft surgery. We evaluated 243 patients (225 males, 18 females, mean age 65 +/- 7.3 years) submitted to venous coronary artery bypass graft surgery and 10-year follow-up (123 +/- 20 months). Global mortality was 17.6% (n = 43), significantly higher in patients with ejection fraction (EF) < 50% (log-rank test p < 0.001). The survivors (n = 200) were subdivided into two groups according to postoperative EF: patients with EF > or = 50% (n = 160) and patients with EF < 50% (n = 40). Multivariate analysis revealed that cardiovascular risk factors (hypertension, diabetes, hypercholesterolemia, smoking), number of grafts and infarct location were not associated with EF reduction. Only multivessel disease was significantly associated with EF reduction (p = 0.008). Preoperative echocardiographic parameter analysis evidenced that regional ventricular wall motion score was significantly higher in patients with reduced EF (EF < 50% 11 +/- 7.5; EF > or = 50% 6 +/- 4.1, p < 0.001) and left ventricular dilation (p < 0.001). Multivariate analysis revealed that the strongest correlates of EF < 50% were left ventricular wall motion score index > 10 (odds ratio 5.8, 95% confidence interval 2.8-11.7) and multivessel disease (odds ratio 9.0, 95% confidence interval 2.6-31.08). This study revealed that echocardiographic detection of preoperative ventricular wall motion score may be useful to assess patients at high risk of ventricular remodeling after venous coronary artery bypass graft surgery.
Left anterior descending grafting with a left internal thoracic artery on a beating heart via a small left anterior thoracotomy is a procedure that is becoming popular, even if not yet standardized. From November 21, 1994 through February 20, 1997, 411 patients underwent a small left anterior thoracotomy; 206 had single-vessel disease, 205 had multiple-vessel disease. The early mortality rate was 1.0% (4 patients); causes of death were cardiac, not operation-related in 3, and non-cardiac in 1. The late mortality rate was 1.4% (6 patients); causes of death were cardiac operation-related in 1, non-cardiac in 3. All patients had a postoperative Doppler-flow velocity assessment; 231 (56.2%) underwent an angiographic control during the first postoperative year. Some patients were selected, as every patient with conduit or anastomotic malfunction underwent angiography. The patency rate was 92.4% (214/231); perfect distal anastomoses were obtained in 87.0% (201/231). With increasing experience and new instruments for left internal thoracic artery harvesting and left anterior descending artery stabilization, from April 21, 1996, patency rate increased to 98.2% (107/109) and perfect patency rate to 95.4% (104/109); results are therefore improving with time. The left anterior small thoracotomy procedure gives acceptable midterm results and is a reasonable alternative to the median sternotomy when the left anterior descending artery needs to be grafted with the left internal thoracic artery.
Anticancer therapy with doxorubicin (DOX) and other quinone anthracyclines is limited by severe cardiotoxicity, reportedly because semiquinone metabolites delocalize Fe(II) from ferritin and generate hydrogen peroxide, thereby promoting hydroxyl radical formation and lipid peroxidation. Cardioprotective interventions with antioxidants or chelators have nevertheless produced conflicting results. To investigate the role and mechanism(s) of cardiac lipid peroxidation in a clinical setting, we measured lipid conjugated dienes (CD) and hydroperoxides in blood plasma samples from the coronary sinus and femoral artery of nine cancer patients undergoing intravenous treatments with DOX. Before treatment, CD were unexpectedly higher in coronary sinus than in femoral artery (342 +/- 131 vs 112 +/- 44 nmol/ml, mean +/- SD; P < 0.01), showing that cardiac tissues were spontaneously involved in lipid peroxidation. This was not observed in ten patients undergoing cardiac catheterization for the diagnosis of arrhythmias or valvular dysfunctions, indicating that myocardial lipid peroxidation was specifically increased by the presence of cancer. The infusion of a standard dose of 60 mg DOX/m(2) rapidly ( approximately 5 min) abolished the difference in CD levels between coronary sinus and femoral artery (134 +/- 95 vs 112 +/- 37 nmol/ml); moreover, dose fractionation studies showed that cardiac release of CD and hydroperoxides decreased by approximately 80% in response to the infusion of as little as 13 mg DOX/m(2). Thus, DOX appeared to inhibit cardiac lipid peroxidation in a rather potent manner. Corollary in vitro experiments were performed using myocardial biopsies from patients undergoing aortocoronary bypass grafting. These experiments suggested that the spontaneous exacerbation of lipid peroxidation probably involved preexisting Fe(II) complexes, which could not be sequestered adequately by cardiac isoferritins and became redox inactive when hydrogen peroxide was included to simulate DOX metabolism and hydroxyl radical formation. Collectively, these in vitro and in vivo studies provide novel evidence for a possible inhibition of cardiac lipid peroxidation in DOX-treated patients. Other processes might therefore contribute to the cardiotoxicity of DOX.
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We evaluated the effect of ischemia and reperfusion on sarcoplasmic reticulum Ca uptake in patients subjected to cardiac surgery. Our series included 16 patients (seven female, nine male, age 63 +/- 2 years): five were subjected to aortic valve replacement, five to aortic and mitral valve replacement, six to coronary artery bypass graft. In each case no clinical, electrocardiographic or echocardiographic evidence of perioperative infarction was observed. Biopsies were obtained from the right atrium of each patient before starting extracorporeal circulation, and after the recovery of spontaneous contractile activity, i.e. after cardioplegia-ischemia-reperfusion. The tissue was homogenized, and oxalate-supported Ca uptake, which represents sarcoplasmic reticulum Ca uptake, was measured in the unfractionated homogenate. The assay was performed under basal conditions and in the presence of 900 microM ryanodine, in order to block sarcoplasmic reticulum Ca release channels. Under basal conditions at pCa = 5.85 the rate of sarcoplasmic reticulum Ca uptake averaged 4.76 +/- 0.37 nmol/min per mg of protein in the pre-ischemic samples, and decreased significantly in the post-ischemic samples (3.09 +/- 0.29 nmol/min per mg, P < 0.01). A significant decrease of Ca uptake after ischemia and reperfusion was observed also in the presence of ryanodine (3.53 +/- 0.48 nmol/min per mg) compared to pre-ischemic values (5.98 +/- 0.56 nmol/min per mg, P < 0.01). Additional experiments showed no change in the Ca sensitivity of Ca uptake in the postischemic samples (Kca = 0.48 +/- 0.02 microM, no significant difference after ischemia and reperfusion). In conclusion, active sarcoplasmic reticulum Ca transport was impaired in human atrial myocardium after reversible ischemia and reperfusion.
BACKGROUND: When right ventricular failure occurs during aortic valvular operation, inadequate myocardial protection may be the culprit. However, other causes of right ventricular failure should be considered, such as air or particulate matter embolization. Right ventricular failure unexpectedly occurred during an aortic valvular operation, and the cause was found to be a mechanical problem with the right coronary ostium. METHODS: A mechanical problem with the right coronary artery (RCA) occurred in 9 patients undergoing aortic valvular procedures, which included isolated aortic valve replacement (4 patients), aortic valve replacement and coronary artery bypass (1 patient), Bentall procedure (2 patients), aortic valve reconstruction (1 patient), and double valve replacement and coronary artery bypass (1 patient). Although myocardial protection was considered to be the cause, a mechanical problem was subsequently identified in the RCA, leading that artery to be bypassed with a segment of saphenous vein. RESULTS: The 1 patient in whom the condition was not recognized at time of aortic valve operation died; at autopsy, a damaged and occluded right ostium was confirmed. The other 8 patients who had the RCA bypassed survived. CONCLUSIONS: We conclude that when right ventricular failure unexpectedly occurs during an aortic valvular operation and does not improve with reperfusion, a mechanical problem in the RCA should be considered. In this situation we recommend that the RCA be bypassed with a segment of saphenous vein graft.
BACKGROUND: We explored the possibility of anastomosing the left anterior internal mammary artery (LIMA) to the left anterior descending artery in a beating heart via a left anterior small thoracotomy. METHODS: This procedure was performed in 155 of 162 scheduled patients; in 7 (4.3%) the left anterior descending artery was not suitable or was too small. The chest was opened in the fourth intercostal space (mean wound length, 10.5 cm) and the LIMA was harvested for about 4 cm. The left anterior descending artery was occluded by means of two 4/0 Prolene (Ethicon, Somerville, NJ) sutures, and the proximal suture was snared. The anastomosis was performed with two 8/0 Prolene sutures while the heart was beating. Early postoperatively all patients underwent repeat angiography or a Doppler flow assessment of the LIMA or both. RESULTS: The LIMA was connected directly to the left anterior descending artery in 144 patients and with interposition of an inferior epigastric artery in 11. In 2 patients the diagonal branch was also grafted using an inferior epigastric artery from the LIMA. One patient (0.6%) died 38 days after the operation due to multiorgan failure. Nine patients (5.8%) had failure requiring a redo operation: 7 (4.5%) early and 2 (1.3%) late. One additional patient had a late percutaneous transluminal coronary angioplasty for anastomotic stenosis. At a mean 5.6 months of follow-up, 143 patients (92.2%) were alive, asymptomatic with or without medical treatment, and without cardiac events. CONCLUSIONS: Left internal mammary artery-to-left anterior descending artery anastomosis performed on a beating heart via a left anterior small thoracotomy is a safe procedure. In selected patients the operation has good early and midterm results.
Minimally invasive coronary artery bypass grafting has recently been introduced into cardiac surgery. The procedure promises to become an important addition to the surgical treatment of coronary artery disease. This current review gives a historical perspective and an overview of this growing field, based on the experience of three international centers with experience with minimally invasive coronary artery bypass grafting. It is predicted that the field will grow, and that future generation of cardiac surgeons will have to become familiar with this new procedure.
A complete revascularization with three or more arterial conduits was achieved, giving the patient, if possible, three blood sources from the in situ arterial grafts (skeletonized bilateral internal thoracic arteries [ITAs] and right gastroepiploic artery). If one of these conduits was not available, a radial artery was used, the proximal anastomosis being constructed on an ITA. The inferior epigastric artery was used if a sequential anastomosis was not advisable or to lengthen another arterial graft. With this strategy, 247 patients underwent surgery from October 1991 through April 1995; 774 arterial conduits were used: 244 left ITAs, 187 right ITAs, 159 right gastroepiploic arteries, 114 radial arteries, and 70 inferior epigastric arteries. The in-hospital and late mortality rates were 1.2% (3 patients) and 1.6% (4 patients), respectively. Of the 240 patients alive, 235 (97.9%) are asymptomatic. We compared the 42-month survival and event-free survival curves of these patients with those of an historical cohort of patients who underwent surgery with mixed (1 left ITA and saphenous vein grafts) revascularization. Whereas the survival rate was similar (97.82% +/- 1.11% vs 99.35% +/- 0.65, P = .174), the event-free survival rate was significantly better in the total arterial group (93.72% +/- 2.1 % vs 85.62% +/- 2.84%, P = .021). We conclude that complete revascularization with three or more arterial conduits is technically feasible with a low mortality rate; the mid-term results allow us to continue this strategy of myocardial revascularization.
In redo coronary artery bypass grafting a left anterior thoracotomy can be used, if necessary, to avoid a dangerous repeat median sternotomy. In 2 patients with a well-functioning left internal mammary artery graft to a left anterior descending artery attached to the sternum, a radial artery was used with the left subclavian artery as the blood source. This technique can be used successfully in selected cases when a left thoracotomy is advisable and an arterial graft is preferred to a saphenous vein.