Coronary artery spasm during coronary artery bypass surgery: Its diagnosis,treatment and prevention

Between 1982 and 1983, we experienced four cases of hemodynamic collapse accompanied by an ST-segment depression in the ECG lead II, shortly after the cessation of cardiopulmonary bypass. The bypass graft flows monitored in these patients during the hemodynamic collapse episodes were remarkably low. In three cases, nitroglycerin (0.5–1 mg) was injected directly into the vein graft, which increased the graft flow suddenly, returned the ST-segment to the baseline, and improved the circulatory condition. Since 1984, however, diltiazem has been used in the cardioplegic solution and postoperative drip infusion. Due to the introduction of this drug, coronary artery spasm has not been seen in any of our patients since. These findings show that the monitoring of ST-segment changes and bypass graft flows are useful in the early diagnosis of coronary artery spasm after myocardial revascularization. Direct infusion of nitroglycerin into the vein graft is effective for the treatment of spasm, while diltiazem is useful in the prevention of coronary artery spasm incidental to myocardial revascularization.     

Effects of intra-coronary and intra-graft administration of nicorandil for coronary spasm after coronary artery bypass grafting

Coronary artery spasm after coronary artery bypass grafting (CABG) is relatively rare, but when it occurs, it is fatal. In cases of circulatory collapse just after surgery, coronary spasm should be suspected, and immediate diagnosis by coronary angiography is necessary. We conducted a study to assess the clinical characteristics of coronary spasm after CABG and the usefulness of intra-coronary and intra-graft administration of nicorandil. Study subjects were 7 patients (6 men and 1 woman, mean age 60.4 years) in whom coronary spasm after CABG was diagnosed angiographically from January 1992 to December 2003. Off-pump CABG (OPCAB) had been performed in 2 patients. Despite continuous administration of nitroglycerin and diltiazem hydrochloride during surgery, sudden circulatory collapse occurred during surgery or within 24 hours after CABG in all 7 patients. All required mechanical circulatory support, and emergency coronary angiography revealed severe graft and native coronary spasms. Intracoronary and/or intra-graft administration of diltiazem hydrochloride or nitroglycerin was not very effective, however, administration of nicorandil was effective for vasodilatation. One patient suffered brain damage and died, but the other 6 patients recovered and were discharged without complication. In conclusion, intra-coronary and/or intra-graft administration of nicorandil appears to be useful for the treatment of coronary spasm after CABG.     

Intraoperative Use of Nifedipine for Hemodynamic Collapse Due to Coronary Artery Spasm Following Myocardial Revascularization

Sudden hemodynamic collapse in the perioperative period following myocardial revascularization may be due to coronary artery spasm. Nitroglycerin has been the standard treatment for this; however, it is not always effective, and the resultant morbidity and mortality are high. We present the case of a patient in whom sudden hemodynamic collapse due to coronary artery spasm was refractory to intravenously administered nitroglycerin but was relieved quickly with sublingually administered nifedipine. In certain selected patients in whom coronary artery spasm is responsible for myocardial collapse, the drug nifedipine may be effective in relieving this spasm and allowing for myocardial recovery.     

Diltiazem provides higher internal mammary artery flow than nitroglycerin during coronary artery bypass grafting surgery.

OBJECTIVES: Perioperative internal mammary artery (IMA) vasospasm in patients undergoing coronary artery bypass grafting (CABG) surgery may lead to morbidity and mortality. Surgical stimulus is one of the common causes of IMA vasospasm. Preventive measures, beside treatment should be taken into consideration to obtain vasospasm free IMA. The effect of a pharmacologic agent on IMA flow when it is administered before harvesting the artery has not been documented. We designed a prospective randomized clinical study to compare the IMA free blood flows in patients receiving either diltiazem or nitroglycerin, starting infusion of study drugs before a surgical stimulus was applied to the IMA region and continuing throughout the isolation period. METHODS: Sixty patients undergoing elective CABG surgery with the left IMA received diltiazem (n=30, 0.05-0.1 mg/kg per hour) or nitroglycerin (n=30, 0.25-2.5 microg/kg per minute) in a randomized manner. Infusions of study drugs were started before applying a surgical stimulus to the IMA region and continued throughout the harvesting period. The first free flow was measured after IMA was cut above its bifurcation and the second after its distal segment was resected. Heart rate, temperature, mean arterial and central venous pressures were recorded. Data were analyzed with Student's t-test and Fischer's exact test. RESULTS: Preoperative and hemodynamic data were similar between the groups. The means of first and second IMA flows in patients treated with diltiazem (53.8+/-30.1 and 72.3+/-35.4 ml/min) were significantly higher than in those treated with nitroglycerin (25.7+/-16.2 and 48.9+/-23.8 ml/min; P=0.000, 0.004, respectively). IMA flows significantly increased after distal segment resection both in diltiazem (34%) and nitroglycerin groups (90%; P= 0.000, 0.000, respectively). CONCLUSIONS: Diltiazem infusion which started prior to harvesting provided higher IMA blood flow compared to nitroglycerin infusion. Considering the percentage of increases in flows after resection of distal segment, the most prone part to vasospasm, we assume that a certain amount of spasm occurred in IMA in spite of infusion of study drugs, such that less with diltiazem and more with nitroglycerin. Diltiazem plays more important role than nitroglycerin in the prevention of vasospasm.     

Coronary artery spasm and ventricular fibrillation after off-pump coronary surgery

Native coronary artery or bypass graft spasm is a rare cause of acute myocardial infarction after coronary artery bypass grafting. This report presents angiographic documentation of native coronary artery spasm following successful multivessel off-pump coronary revascularization, which caused myocardial ischemia leading to inferior wall myocardial infarction and ventricular fibrillatory arrest.     

老年冠状动脉粥样硬化性心脏病患者桡动脉抗痉挛药物选择的实验研究

目的 比较地尔硫(蕈)、罂粟碱及硝酸甘油缓解老年冠状动脉粥样硬化性心脏病(冠心病)患者桡动脉痉挛的能力.方法 2009年7月至2010年3月,应用自体桡动脉对60例70岁以上老年冠心病患者行冠状动脉旁路移植术(CABG),收集术中剩余桡动脉,采用血管环灌流技术,分别比较3种抗痉挛药物对离体痉挛桡动脉的缓解作用.所有患者随机分为3组,自桡动脉远端分别向桡动脉管腔内注入地尔硫(蕈)、罂粟碱及硝酸甘油,测量注射前后30 s血流量及血流动力学指标(心率、平均动脉压、中心静脉压).结果 三种抗痉挛药物可不同程度缓解桡动脉痉挛,最终缓解率均超过80%.硝酸甘油可完全舒张桡动脉,舒张能力高于地尔硫(蕈)及罂粟碱.注射前后患者血流动力学指标差异无统计学意义,硝酸甘油[(42±10)ml/30 s比(28±7)ml/30 s,P<0.05]可增加桡动脉血流量,地尔硫(蕈) [(23±10)ml/30 s比(25±8)ml/30 s,P>0.05]与罂粟碱[(25±10)ml/30 s比(24±9),P>0.05]对桡动脉血流无明显影响.结论 硝酸甘油可有效缓解桡动脉痉挛,改善血流;相比于地尔硫(蕈)及罂粟碱,硝酸甘油是较为适宜的老年冠心病患者桡动脉抗痉挛药物.     

冠状动脉旁路移植术后早期紧急再次手术

目的 探讨冠状动脉旁路移植(CABG)术后围术期急性心肌缺血的病因和外科治疗.方法 2001年1月至2009年1月,28例CABG术后早期进行了紧急再次手术.其中男18例,女10例.平均年龄54岁.主要病因包括早期移植物栓塞、乳内动脉(IMA)异常、靶血管吻合口异常,桡动脉(RA)痉挛、心肌血管化不完全.首次手术到再次手术时间间隔1～48 h,平均8 h.紧急再次手术中仅2例选择非体外循环不停跳手术,余均在体外循环心脏停跳下CABG.再次手术包括:对异常移植物尽可能去除,选择重新吻合或远端加一旁路血管.对RA持续痉挛者拆除后用静脉再次行旁路手术.再次手术中给予充分再血管化.结果 手术死亡2例.术后1～14天死亡8例.16例术后放置主动脉内球囊反搏(IABP)辅助,其中2例同时进行体外膜式氧合器(ECMO)辅助,2例同时选择左心辅助装置(LVAD).18例生存者均无严重并发症.结论 CABG术后早期急性严重心肌缺血病死率高.早期诊断和及时外科处理可以提高生存率.强调术前、术后预防的重要性.

Abstract：

Objective To explore the cause of acute myocardial ischemia early after coronary artery bapass graft (CABG) and surgical management on it. Methods From 2001 to 2009, 28 patients underwent urgent reoperation early after CABG due to acute myocardial ischemia. The incidence of reoperation is about 0.02%. The cause of reoperation inclouded early graft occlusion (10 cases) ,IMA damage or injury during harvesting(9 cases), inexactitude distal anastomosis(2 cases)and radial artery spasm(4 cases). The mean interval time between two operations was 8 hours. Reoperation was done under offpump bypass in 2 patients and on-bypass used in other patients. Unsatisfactoey graft were substituted with new graft material and thrombotic was removed. If LIMA was the reson for myocardial ischemia, an additional vein graft was inserted. The spasm radial artery were substituted with new vein graft. Completely revascularization was used in re-do CABG. Results Two patients died during reoperation. 8 patients was died between 1 day and 14 days after reoperation. IABP was used in 16 patients,which 2 patients received ECMO suppord and 2 patient received LVAD suppord at mean time. Conclusion There have very high mortality in acute myocardial ischemia early after CABG. The early diagnosis and correct surgical management can improve the rates of survival. The active prevent should be emphasized during the first CABG.     

Coronary artery spasm following coronary artery surgery

Coronary artery spasm during the early postoperative period following cardiopulmonary bypass for coronary artery surgery can be an unrecognized cause of sudden, severe cardiopulmonary collapse. The literature regarding perioperative coronary artery spasm is reviewed, and methods of prevention, diagnosis, and treatment are suggested. Preoperative angina at rest appears to be an important identifying factor in patients who experience postoperative coronary spasm. Anatomically, the presence of a relatively normal, dominant right coronary may also indicate increased risk for early post-coronary bypass spasm. Acute hypotension is often the first sign of coronary artery spasm, and conventional treatment methods may only worsen the vasospastic reaction. Peripheral intravenous nitroglycerin infusion has often been unsuccessful treatment while intragraft or intracoronary nitroglycerin injection or administration of calcium channel-blocking drugs, or both, has proven to be effective in reversing the coronary artery spasm and ventricular dysfunction. Reluctance to use vasodilating agents must be overcome, even in the face of hypotension, when evidence of spasm is present.     

Use of extrafascially harvested radial artery for coronary artery revascularization: technical considerations

BACKGROUND: The use of the radial artery for coronary artery revascularization was abandoned due to its tendency for spasm; the revival was attributed to improved harvesting technique as well as the use of calcium channel blockers. METHODS: Between February 1996 and June 1997, the radial artery graft was used in 77 of 89 consecutive patients undergoing coronary artery bypass graft surgery. Only the patients with positive Allen's test or forearm deformity were denied the use of the radial artery. We used an extrafascial, no-touch technique using low-strength electrocautery for harvesting the radial artery. Calcium channel blockers were not used in any of these patients. RESULTS: There were no early deaths. No patient sustained perioperative myocardial infarction or required intra-aortic balloon pump. Only one patient required inotropic agents. Three noncardiac late deaths occurred during the follow-up of 6 to 24 months. No early or late ischemic or functional forearm disability was reported in any of the patients. CONCLUSIONS: The radial artery is easy to harvest and safe to use routinely. When harvested extrafascially, diltiazem infusion may not be necessary. Maximal arterial-global revascularization using the left internal thoracic artery-to-left anterior descending coronary artery and radial artery-to-circumflex artery system may improve the early and long-term results.     

A new aspect of coronary artery spasm induced by cardiac surgery

Five patients developed coronary artery spasm during open heart surgery in our institute between 1984 and 1988. One patient was undergoing coronary artery bypass grafting and the other four valvular surgery or surgery for congenital heart disease. In one of the patients undergoing non-coronary surgery, the preoperative induction of right coronary artery spasm by ergonovine had been documented angiographically while the remaining three patients did not possess organic or functional coronary disease. All five patients exhibited a sudden onset of hemodynamic collapse with ventricular tachyarrhythmias or ST elevation during the early period of reperfusion, the time to onset being 89.2±84.8 minutes after unclamping of the aorta. In addition, contraction of the right ventricular free wall was severely impaired. Although one patient died due to left ventricular rupture caused by direct cardiac massage, the early mortality thus being 20 per cent, the other four were successfully treated with the intravenous administration of nitroglycerin and diltiazem. Three patients required the assistance of intraaortic balloon pumping for severe cardiac failure. Thus, during open heart surgery, coronary artery spasm can occur even in patients without organic coronary lesions and the possible mechanisms of this condition are discussed herein.     

A new aspect of coronary artery spasm induced by cardiac surgery

Five patients developed coronary artery spasm during open heart surgery in our institute between 1984 and 1988. One patient was undergoing coronary artery bypass grafting and the other four valvular surgery or surgery for congenital heart disease. In one of the patients undergoing non-coronary surgery, the preoperative induction of right coronary artery spasm by ergonovine had been documented angiographically while the remaining three patients did not possess organic or functional coronary disease. All five patients exhibited a sudden onset of hemodynamic collapse with ventricular tachyarrhythmias or ST elevation during the early period of reperfusion, the time to onset being 89.2 +/- 84.8 minutes after unclamping of the aorta. In addition, contraction of the right ventricular free wall was severely impaired. Although one patient died due to left ventricular rupture caused by direct cardiac massage, the early mortality thus being 20 per cent, the other four were successfully treated with the intravenous administration of nitroglycerin and diltiazem. Three patients required the assistance of intraaortic balloon pumping for severe cardiac failure. Thus, during open heart surgery, coronary artery spasm can occur even in patients without organic coronary lesions and the possible mechanisms of this condition are discussed herein.     

Coronary bypass surgery using arterial conduit and its pitfall]

Three patients with spasm of internal mammary arteries and gastroepiploic artery immediately after coronary bypass surgery were reported. On completion of the revascularization, all patients could not be weaned from cardiopulmonary bypass. The flow velocity waveforms of the arterial grafts measured by pulsed Doppler velocimeter showed only small systolic component without diastolic flow and the palpation revealed profound spasm partially in the arterial conduits. Although all patients could be weaned from cardiopulmonary bypass only after insertion of a saphenous vein graft, two of them died on the next day. In all patients, free flow measured prior bypass was considered to be sufficient and a technically satisfactory anastomosis was felt to be performed. If a profound hemodynamic instability as a result of intractable spasm of arterial conduit occurred after completion of coronary bypass surgery, an additional saphenous vein graft should be placed before discontinuation of cardiopulmonary bypass.     

Vasoactive drug effects on blood flow in internal mammary artery and saphenous vein grafts

The internal mammary artery is a dynamic coronary graft, whereas the saphenous vein graft is passive. Therefore, potential exists not only for beneficial vasodilation but also for catastrophic spasm of the artery. The purpose of this study was to examine blood flow in the internal mammary and saphenous vein grafts during infusion of drugs that are commonly used after cardiac operations. A canine right heart bypass preparation allowed precise control of cardiac output, blood pressure, and heart rate, which were maintained constant during drug infusion. Both the internal mammary and saphenous vein grafts were constructed so that they perfused the same coronary bed: They were anastomosed in a Y fashion to a ligated anterior descending coronary artery. Electromagnetic flow probes measured graft flow (with the other graft occluded) before and after 15 minutes of drug infusion. The order of drug infusion was randomized and changes were compared by tests for paired differences. Phenylephrine (2 micrograms/kg/min) decreased flow in both the internal mammary and saphenous vein grafts, whereas norepinephrine (0.1 microgram/kg/min) increased flow in both grafts. Epinephrine (0.05 microgram/kg/min) increased mammary artery flow 16% +/- 6% but decreased saphenous vein graft flow 9% +/- 7%. Nitroglycerin (1 microgram/kg/min) significantly increased internal mammary flow (36% +/- 13%), from 47 +/- 7 to 59 +/- 7 ml/min (p less than 0.01), whereas flow decreased significantly in the saphenous vein graft 14% +/- 3%, from 64 +/- 9 to 59 +/- 8 ml/min (p less than 0.01). Nitroprusside (1 microgram/kg/min) decreased mammary artery flow 12% +/- 2%, from 50 +/- 7 to 44 +/- 7 ml/min (p less than 0.01), but increased saphenous vein graft flow 25% +/- 8%, from 64 +/- 9 to 77 +/- 7 ml/min (p less than 0.01). All hemodynamic variables were unchanged, except for norepinephrine, which significantly increased the first derivative of left ventricular pressure. The results suggest that flow through the canine internal mammary artery is changed by the drugs commonly used in perioperative management. Epinephrine and nitroglycerin increased internal mammary artery flow and decreased saphenous vein graft flow, whereas nitroprusside had the opposite effect. The vascular reactivity of the internal mammary artery must be considered when these drugs are used after coronary revascularization.     

Effects of vasoactive drugs on flows through left internal mammary artery and saphenous vein grafts in man.

Vasoactive agents are commonly used in the postcardiopulmonary bypass period to elevate the mean arterial pressure of myocardial revascularization patients. Concern exists that administration of vasoactive agents in this setting may affect flow through saphenous vein and internal mammary artery grafts. Twenty-eight patients were randomly assigned to receive one of the six two-drug combinations of phenylephrine, norepinephrine, and epinephrine. After termination of cardiopulmonary bypass baseline, hemodynamic measurements and electromagnetic flow probe measurements of saphenous vein and internal mammary artery graft flow were made. The first agent was then infused to elevate mean arterial pressure 20 mm Hg. After 5 minutes of stability, hemodynamic and graft flow measurements were repeated. The infusion was terminated, 5 minutes of stability were obtained, and baseline measurements were repeated. The second agent was then infused, and measurements were repeated after a 5-minute stabilization period. Phenylephrine induced a nonsignificant increase in saphenous vein graft flow (68 +/- 31 versus 81 +/- 49 ml/min) and a significant decrease in internal mammary artery graft flow (40 +/- 16 versus 32 +/- 12 ml/min). Norepinephrine induced a significant increase in saphenous vein graft flow (80 +/- 39 versus 97 +/- 39 ml/min) and no significant change in internal mammary artery graft flow (44 +/- 20 versus 45 +/- 20 ml/min). Epinephrine induced a significant increase in both saphenous vein (82 +/- 38 versus 96 +/- 40 ml/min) and internal mammary artery (38 +/- 12 versus 55 +/- 24 ml/min) graft flows. We conclude that administration of vasoactive agents in the postcardiopulmonary bypass period may significantly affect saphenous vein and internal mammary artery graft flows.     

Nitroglycerin is superior to diltiazem as a coronary bypass conduit vasodilator

BACKGROUND: Recent reports of improved radial artery patency have been attributed, in part, to routine use of diltiazem to prevent vasospasm. However, diltiazem is costly, and its use may be associated with negative inotropic and chronotropic side effects. This study compares the vasodilatory properties of diltiazem to those of nitroglycerin. METHODS: In vitro, with the use of organ chambers, the vasodilatory properties of diltiazem and nitroglycerin were compared in matched segments of radial artery, internal thoracic artery, and saphenous vein that were harvested from the same patients (n = 11). The vasodilatory response of the radial artery to intravenous diltiazem or nitroglycerin was compared in vivo (n = 10) with the use of ultrasonographic measurements of radial artery diameter. RESULTS: The maximum relaxation of radial artery (100% +/- 4%), internal thoracic artery (96% +/- 4%), and saphenous vein (100% +/- 3%) to nitroglycerin were significantly greater than the response to diltiazem (33% +/- 6%, 22% +/- 7%, and 34% +/- 5%, respectively; P <.001). The thromboxane mimetic, U46619, induced radial artery spasm with a median effective concentration of 3.7 +/- 0.8 nmol/L. Physiologic concentrations of nitroglycerin (0.1+/- micromol/L) significantly inhibited the radial artery response to U46619 (median effective concentration, 6.2 +/- 1.1 nmol/L; P =.046), whereas diltiazem (1 micromol/L) did not (median effective concentration, 3.7 +/- 0.8 nmol/L; P =.64). In vivo, nitroglycerin increased radial artery diameter 22% +/- 3%, which was significantly greater than diltiazem (3% +/- 0.5%; P =.001). CONCLUSION: Nitroglycerin is a superior conduit vasodilator and is more effective in preventing graft spasm than diltiazem. Nitroglycerin should be strongly considered as the drug of choice to prevent conduit spasm after coronary bypass grafting.     

Revival of the radial artery for coronary artery bypass grafting.

Eighteen years after its first introduction for coronary artery revascularization, the radial artery (RA) was reinvestigated because of unexpected good long-term results in the early series. Since July 1989, 104 patients underwent myocardial revascularization using 122 RA grafts (18 patients received two grafts). The left internal mammary artery (IMA) was concomitantly used as a pedicled graft in 100 cases and the right IMA in 19 cases; a free IMA graft was used in 29 cases and a saphenous vein graft in 24 cases. A mean of 2.8 grafts per patient were performed. Nine patients underwent associated procedures: carotid endarterectomy (3), aortic valve replacement (3), Bigelow procedure (1), and mitral valve repair (2). The target artery receiving the RA was the circumflex (n = 59), diagonal (n = 29), right coronary (n = 27), and left anterior descending (n = 7). One patient died (0.96%) and 2 had perioperative myocardial infarct. Sternal wound infection was noted in 3 cases of double IMA implantation. No ischemia of the hand was observed. All patients received diltiazem started intraoperatively and continued after discharge. In addition aspirin (100 mg/day) was given at discharge. Early angiographic controls (less than 2 weeks) were obtained in the first 50 consecutive patients and revealed 56 of 56 patent RA grafts, 48 of 48 patent left IMA grafts, 11 of 11 patent right IMA grafts, 14 of 18 patent free IMA grafts, and 8 of 9 patent vein grafts.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thermographic evaluation of myocardial cooling and intraoperative control of graft patency in patients with coronary artery disease

Intraoperative thermographic evaluation of regional myocardial cooling induced by cardioplegia, in patients with coronary artery disease, was conducted in 22 cases. Pictures were obtained at the beginning of the cardiopulmonary by-pass, after general cooling and during cardioplegic infusion. Uneven myocardial cooling was observed related to the degree of coronary artery stenosis. After the distal anastomosis of the saphenous vein by-pass graft was completed, injection of cold solution in to the graft showed marked cooling of the dependent myocardium, proving the patency of the graft. In the case of internal mammary artery graft (IMA), after the anastomosis was completed, releasing the bull-dog clamp on the IMA graft, allowed a flow of relatively warm (30 degrees C) blood in the anterolateral wall of the cold (20 degrees C) heart. A warm spot appeared in the thermographic pictures, assessing the patency of the IMA graft. Thermography appears to be a useful tool during myocardial revascularization in order to assess proper myocardial cooling during cardioplegia, and to check intraoperative patency of saphenous vein graft and IMA graft. The use of a special mirror prevents interference with the surgeon's work.     

A comparative study on in vitro and in vivo effects of topical vasodilators in human internal mammary, radial artery and great saphenous vein

Objective: As an important prognostic factor of coronary artery bypass grafting (CABG), graft vasospasm can be observed in all currently used graft conduits. Radial artery (RA) vasospasm is more prone to occur in comparisons with internal mammary artery (IMA) and great saphenous vein (GSV). There is still controversy about which antispasmodic agent is superior to different grafts, especially to RA conduits. The aim of this pilot study was to investigate the relaxation response of four topical vasodilators to different in vitro grafts and how these vasodilators affect the blood flow of the vessel in situ during RA harvesting. Materials and methods: Vasodilatory properties of diltiazem, nitroglycerin, urapidil and nicorandil were compared in matched patient-specific segments of RA, IMA and GSV harvested from 12 patients. The vasodilatory response of the RA to intraradial administration of nitroglycerin, diltiazem and urapidil was compared in vivo (n=10 per group) by assessing the free blood flow of RA. Results: (1) The maximal relaxations occurring with urapidil, nitroglycerin and nicorandil in IMA, RA and SGV were significantly greater than that with diltiazem. The reactivity of all three graft conduits showed similar relaxation with nitroglycerin or with diltiazem, but the relaxation with urapidil in RA showed greater than that of IMA and GSV, and RA and GSV showed greater relaxation with nicorandil than IMA. (2) A dose of 10(-5)mol/l of nitroglycerin, urapidil and nicorandil but not diltiazem significantly inhibited the RA response to PE. (3) In vivo, urapidil and nitroglycerin significantly increased the RA blood flow, the potency of which was greater than that caused by diltiazem. Conclusions: (1) Comparing with nicorandil, urapidil and diltiazem, nitroglycerin caused a significant relaxation in all three graft vessels tested. (2) Nitroglycerin, nicorandil and urapidil were more effective in preventing RA spasm than diltiazem.     

Direct coronary artery surgery for coronary artery occlusive disease

Surgical revascularization of the myocardium for coronary artery occlusive disease has gained great impetus over the past five years with the advent of successful methods of direct surgical reconstruction of the coronary arteries. Seventy-five patients underwent direct coronary artery surgery for ischemic heart disease over the past two and a half years. The indication for coronary arterial revascularization was angina in forty-eight patients, congestive heart failure in twenty-four patients, and recurrent myocardial infarction in three patients. In this group of seventy-five patients there were 105 aortocoronary saphenous vein bypass grafts, five internal mammary-coronary artery bypass grafts, and thirty-five distal endarterectomies combined with aortocoronary vein bypass grafts. Direct coronary artery surgery was combined with resection of a left ventricular aneurysm in seven patients and with aortic valve replacement in three. A single coronary artery was reconstructed in twenty-seven cases and two of the three major coronary arteries were reconstructed in thirty-nine cases.     

Coronary artery spasm during coronary artery bypass surgery]

We report two cases of coronary artery spasm during coronary artery bypass surgery. As one of the complications during cardiac surgeries, coronary vasoconstriction occurs mainly after coming off cardiopulmonary bypass. The factors responsible for the spasm include high endogenous catecholamine levels due to inadequate anesthesia and hypothermia, exogenous catecholamines for circulatory support, various chemical mediators and combination of these factors. Coronary artery spasm was suspected strongly because of sudden ischemic change in electrocardiography and simultaneous aggravation of circulatory parameters, which improved immediately after direct injection of coronary vasodilators into vein graft. This method, popular in coronary angiography and catheterization, is effective for release of coronary-artery spasm observed particularly after cardiopulmonary bypass. Then mechanical circulatory assist is readily available to treat possible systemic side effect of the vasodilators.