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Eur J Cardiothorac Surg 2003;24:830-833
© 2003 Elsevier Science NL
Case report |
Division of Cardiac Surgery, University of Verona Medical School, Ospedale Civile Maggiore Borgo Trento, Piazzale Stefani 1, 37126 Verona, Italy
Received 10 February 2003; received in revised form 4 June 2003; accepted 16 June 2003.
* Corresponding author. Tel.: +39-45-807-2476; fax: +39-45-807-3308
e-mail: strimboli{at}katamail.com
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Abstract |
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 Top Abstract 1. Background2. Case report3. Discussion4. ConclusionsReferences |
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Key Words: Coronary artery spasm • Coronary artery by-pass grafting complications
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1. Background |
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TopAbstract1. Background2. Case report3. Discussion4. ConclusionsReferences |
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It can severely complicate the immediate postoperative period of patients undergoing coronary artery by-pass grafting (CABG), leading to myocardial ischemia or infarction, life-threatening arrhythmias, persistent hypotension and cardiac arrest.
We report on a patient who underwent an off-pump myocardial revascularisation (OPCAB) and experienced a persistent right coronary spasm in the immediate post operative period.
A role of the technique used for myocardial stabilisation is suspected.
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2. Case report |
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TopAbstract1. Background2. Case report3. Discussion4. ConclusionsReferences |
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Myocardial stabilisation and vascular flow control were achieved by circling the right coronary artery and the diagonal branch, proximally to the anastomotic site only, with silastic loops. The coronary blood flow was temporary interrupted for each anastomosis time by gently snaring the silastic loops. No endoluminal shunts were used. Since the median portion of the right coronary artery was found not diseased, the anastomosis was performed at this site thus allowing less manipulation of the heart to achieve exposure.
Coronary anastomosis were performed after 3 min of preconditioning and 5 min of reperfusion. During the procedure hemodynamic and electrocardiografic parameters remained stable.
At the admission in the intensive care unit the post operative ECG was unremarkable and the hemodynamic status was satisfactory.
Shortly after admission, while the patient was being weaned from the ventilator, he experienced an episode of systemic persistent hypotension (80/60 mmHg) accompanied by significant modification of the ECG: ST segment elevation in Lead D3, important reduction of the R wave in Lead AVF, D3, and ST segment depression in Lead V3–6, D1 and AVL.
The situation rapidly deteriorated with ventricular fibrillation, which was converted into sinus rhythm by a single 300 J electric shock.
The hemodynamic status was then stabilised after insertion of an intra-aortic balloon pump and intravenous nitroglycerine infusion.
Echocardiographic evaluation showed a new akynetic area in the inferior left ventricular wall.
The patient was thus rushed back to the operating room, the sternotomy was reopened and the patency of the grafts was verified. Both the arterial and venous grafts appeared well functioning. Therefore the chest was closed and the patient was taken to the catheterisation laboratory for a new coronary artery angiogram, which confirmed patency of the grafts, but revealed a diffuse spasm of the native right coronary artery (Fig. 2a) .
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The electrocardiographic ST segment elevation was reversed and the ECG showed only the reduction of the R wave in Lead AVF and D3. In addition, the arterial pressure gradually returned to basal level and the infusion of dopamine could be weaned. Troponine I peak reached 25 ng/ml and the echocardiogram showed inferior akynesia with an otherwise normal global contractility of the left ventricle, with the appearance of Q-waves in the inferior leads.
On the 3rd post operative day, intraaortic counterpulsation could be discontinued, the intravenous infusion of nitroglycerine was tapered over 4 days.
The remaining postoperative course was uneventful and the patient was discharged home on 12th postoperative day in good clinical conditions.
At the 3 year follow-up control, the patient is alive in good clinical conditions and refers no recurrence of angina since surgery.
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3. Discussion |
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TopAbstract1. Background2. Case report3. Discussion4. ConclusionsReferences |
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Myocardial revascularisation is indicated in patients with documented coronary artery spasm only when there are concomitant critical coronary artery obstructive lesions.
Coronary artery spasm may occur during surgery or in the immediate post operative period in patients undergoing CABG, with an incidence as high as 0.8% [1] up to 1.3% [2] according to different reports. However, considering that an exact diagnosis can be achieved only by coronary angiography, the real incidence is suspected to be much higher.
Patients with a preoperative history of variant angina may be by far, more predisposed to perioperative coronary spasm.
According to the literature the right coronary artery is, in the large majority of the cases, the artery interested by the spasm [3], but some cases of left coronary artery spasm have been reported as well [4].
To the best of our knowledge, the case we report on is the first described of post-operative coronary artery spasm after OPCAB.
The manifestations of postoperative coronary artery spasm range from arrhythmia to ST segment elevation, hemodynamic instability, severe hypotension and circulatory collapse, low cardiac output and cardiac arrest. When the spasm is not promptly resolved it may have irreversible and life-threatening consequences such as myocardial infarction, low cardiac output and arrhythmias.
Many etiologic factors have been advocated to explain the pathogenesis of postoperative coronary arterial spasms: coronary artery trauma due to surgical manipulation or to compression by chest drain tubes, alkalotic blood pH, alpha adrenergic stimulation, low body temperature, release of vasospastic factors by the platelets (Tromboxane A2) damaged during cardio-pulmonary bypass [5].
We could identify none of this factors in the pathogenesis of the spasm in our patient, except for an external coronary artery trauma due to the silastic loop retraction and snaring during ischemic preconditioning and during the anastomosis. Silastic band circling is a very simple and cheap method to achieve myocardial stabilisation and temporary coronary flow interruption. However, we speculate that the trauma due to external traction and compression on the arterial wall might induce diffuse coronary spasm, with the potential to appear hours after operation.
The exact diagnosis of coronary artery spasm can be reached only by coronary angiography, but spasm must be kept in consideration in the differential diagnosis every time a patient undergoing myocardial revascularisation experiences hemodynamic instability with the evidence of transmural ischemia. In such a situation, we strongly advise coronary angiography rather than surgical re-exploration which has a low diagnostic yield and may represent a fatal waste of time.
Furthermore, the usual intravenous therapies alone often seem to be ineffective for resolution of coronary artery spasm. Many therapeutic protocols have been proposed either for the prevention or for the postoperative treatment, utilising different drugs such as: verapamil, nifedipine, nitroglycerine, amyl nitrate.
In our experience, direct intracoronary high dose nitroglycerine infusion proved to be the only effective therapy for the complete resolution of coronary spasm. We suggest to initiate it as soon as the coronary catheterisation is accomplished. This may be associated with intravenous infusion of calcium channel blocking agents and/or nitroderivates, that must be continued for at least 48 h.
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4. Conclusions |
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TopAbstract1. Background2. Case report3. Discussion4. ConclusionsReferences |
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Surgeons must be aware that silastic loop coronary retraction and temporary snaring, even though simple and cheap method to achieve stabilisation and bloodless surgical field, can lead to persistent coronary artery spasm, immediately as well as few hours after operation.
Prolonged postoperative coronary spasm may lead to myocardial infarction (as the case herein described demonstrates), or exitus.
Coronary angiography is strongly advised in patients with hemodynamic instability with the EKG and echocardiographic evidence of trasmural myocardial ischemia in order to differentiate coronary spasm from CABG or native coronary occlusion and to establish the most appropriate therapy.
Coronary spasm is often refractory to the usual intravenous drugs infusions, while direct intra coronary or intra graft administration of high doses nitroderivates or calcium channel blockers may be the only effective treatment to reverse it.
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Acknowledgments |
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References |
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TopAbstract1. Background2. Case report3. Discussion4. ConclusionsReferences |
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