Left Main Coronary Artery Dissection Detected By Intravascular Ultrasound Following Angiographically Successful Percutaneous C

Case Report. A 69-year-old smoker, hypertensive, hypercholesterolaemic, non-insulin dependent diabetic presented to the hospital ten days following an anterior myocardial infarction. Coronary angiography revealed a critical mid-vessel stenonsis in the left anterior descending artery (LAD) and a tight lesion in the proximal left circumflex artery (LCx) (Figure 1). The right coronary artery (RCA) was occluded proximally with distal retrograde filling. The 12-lead ECG showed Q waves in leads V2–V4, but due to the patient’s ongoing symptoms of chest pain and the presence of dynamic ST-T changes in the antero-septal leads, we proceeded to percutaneous coronary intervention (PCI) to the LAD. Using a JL4 6 French guide catheter, a PT graphix guide wire (Boston Scientific, Cedex, France) was advanced into the distal LAD and the mid-vessel lesion was pre-dilated with a 2 x 15 mm balloon to 10 atm. Following this, a 2.75 x 28 mm Express stent (Boston Scientific, Galway, Ireland) was deployed with some difficulty, necessitating aggressive guide catheter manipulation. On the post-stent deployment angiogram, there appeared to be a “new” lesion within the proximal LAD (Figure 2), which may have been related to a guide catheter dissection following deep intubation of the guide during the preceding stent positioning and deployment. This was treated directly with a 3.5 x 9 mm AVE stent (Medtronic, Inc. Minneapolis, Minn.). Although the stented LAD segment looked satisfactory on repeat angiography, there was a suspicious appearance of a small “filling defect” within the LAD proximal to the stent (Figure 3). We decided to assess the LMCA by intravascular ultrasound (IVUS) (CVIS, Inc., Sunnyvale, Calif.). The IVUS study showed a significant dissection with the proximal LAD (Figure 4) which extended back to the mid-left main coronary artery (LMCA) (Figure 5). The dissection was sealed with a 3.5 x 15 mm Zeta stent (Guidant), extending from the proximal LAD back into the mid-LMCA. The LMCA segment of the stent was post-dilated with a 4 mm balloon. This led to a good angiographic result (Figure 6) and repeat IVUS showed a well deployed stent with good apposition to the vessel wall. The procedure was covered with elective abciximab (ReoPro™) and the patient was maintained on a month’s course of clopidogrel and long-term aspirin. Patient Management. This case illustrates the potential limitations of angiography as well as the advantages and superiority of IVUS in assessing coronary anatomy. Although the use of IVUS within interventional centers is predominantly in the context of clinical trials and research, it often proves to be an invaluable clinical tool. In our case, the angiographic appearance in Figure 3 was suspicious, but not diagnostic of the LMCA dissection. However, IVUS guided our management strategy by clearly demonstrating the dissection which was then appropriately treated. Due to the complicated nature of this interventional procedure, we elected to only treat the infarct-related artery and to follow the patient up clinically in order to assess any symptoms that may necessitate further intervention on the LCx artery. Three months following the interventional procedure, the patient is well and asymptomatic and is due to undergo elective angiography to assess the LMCA stent in two months time. How Would You Manage This Case? Larry J. Diaz-Sandoval, MD and Ik-Kyung Jang, MD Knight Center for Interventional Cardiovascular Therapy Massachusetts General Hospital, Harvard Medical School Boston, Massachusetts This case illustrates the incomplete nature of the images provided by coronary angiography or “luminography,” and the superiority of the images and information obtained with intravascular ultrasound (IVUS), which allows to examine the lumen and the vessel wall, providing diagnostic information that can guide the appropriate interventional therapy and improve long-term prognosis. The use of IVUS has proven to be beneficial in a variety of settings, two of which are pertinent to this case: 1) IVUS is useful to interrogate areas that have a “suspicious” angiographic appearance,¹ and in this case allowed the authors to identify a dissection, as the pathology responsible for the “hazy” appearance or “filling defect” present proximal to the stent delivered in the LAD.² IVUS evaluation identifies “unfavorable” non-flow-limiting dissections that might be prone to acute occlusion. 2) IVUS helps to guide therapy by helping to choose the correct size of the stent, confirm good strut apposition and complete lesion coverage, which was correctly done in this case. The authors however did not provide a measurement of the cross-sectional area or the minimal luminal area at the stent site, and its relationship to the distal reference lumen area, which are well-known predictors of long-term outcomes after stenting.³ It also seemed that a 9 mm stent was too short in this case, which necessitated a placement of another stent. Regarding pharmacotherapy, we agree with the use of abciximab, which in our opinion should have been started at the beginning of the procedure given the unstable clinical picture that the patient presented with. Although not clearly stated, it seems that the authors used abciximab as bailout therapy, once the dissection was diagnosed. We also support the use of clopidogrel, which in this case should have been prescribed for a longer period of time, based in well-known data supporting the use of long-term clopidogrel after percutaneous coronary interventions.^3,4 However, we disagree with the management of the left circumflex lesion. The authors did not mention that the ostial left circumflex was partially jailed (“pinched”) after the stent deployment into the left main and should have been treated with kissing balloon angioplasty at that time. In summary, this case represents a good example of the clinical usefulness of IVUS. Although not routinely used, this intravascular imaging technology can be a powerful tool in interventional cardiology. References: 1. Ziada K, Tuzcu EM, De Franco AC, et al. Intravascular ultrasound assessment of the prevalence and causes of angiographic “haziness” following high-pressure coronary stenting. Am J Cardiol 1997;80:116–121. 2. Hong M-K, Park S-W, Lee CW, et al. Intravascular ultrasound in stenting of unprotected left main coronary artery stenosis. Am J Cardiol 1998;82:670–673. 3. Mehta SR, Yusuf S, Peters RJ, et al. Clopidogrel in Unstable angina to prevent Recurrent Events trial (CURE) Investigators. Effects of pretreatment with clopidogrel and aspirin followed by long-term therapy in patients undergoing percutaneous coronary intervention: the PCI-CURE study. Lancet 2001;358(9281):527–533. 4. Steinhubl SR. Berger PB. Mann JT 3rd. et al. CREDO Investigators. Clopidogrel for the Reduction of Events During Observation. Early and sustained dual oral antiplatelet therapy following percutaneous coronary intervention: a randomized controlled trial. JAMA 2002;288:2411–2420. John J. Young, MD The Lindner Center for Research & Education The Ohio Heart Health Center, Cincinnati, Ohio The rapidly evolving advances in interventional cardiology, including newer devices with improvement in performance characteristics, have allowed catheter-based revascularization procedures to be extended to an ever increasing number and complexity of patients. Confidence in these technologies however, needs to be tempered by an evidence-based clinical strategy that will yield the best long-term result for the patient. Following an unexpected complication, it is beneficial to re-trace the steps involved in the procedure to assess what strategies could have been employed to avoid the complication, including the decision to proceed with the intervention. This case represents a patient presenting ten days after a myocardial infarction with recurrent symptoms and dynamic ECG changes prompting cardiac catheterization. Coronary angiography demonstrated significant three-vessel coronary artery disease with an occluded RCA filling from collateral flow and high grade disease in the LAD and LCx arteries. The patients’ left ventricular function is not mentioned nor is co-morbid illnesses. Assuming the patient was a candidate, surgical revascularization should also be considered in this 69-year-old with multiple risk factors, including diabetes mellitus, to try and optimize a long-term revascularization result. The authors elected to proceed with catheter-based revascularization of the LAD artery believed to be the source of the patients’ clinical symptoms. Deployment of a relatively long stent in the mid-LAD required aggressive guide catheter manipulation most likely responsible for the dissection complication. Aggressive catheter maneuvers are fortunately often tolerated by patients with focal disease and more elastic vessels. Diffusely diseased or calcified coronary arteries are less elastic and forgiving with these techniques. Following deployment of a second stent in the proximal LAD, the authors recognized the angiographic appearance of a filling defect prompting IVUS interrogation. Intravascular ultrasound is a valuable tool in these clinical scenarios and ideally should be available with operators trained in its use. This led to a third stent being deployed in the left main coronary artery that fortunately did not appear to obstruct flow into the LCx distribution by subsequent angiography. The final image demonstrated a satisfactory angiographic result. Adjunctive pharmacotherapy is very important in this case especially considering the total length (52 mm) of non-drug-eluting stented segment in the left main and LAD arteries. The use of adjunctive GP IIb/IIIa inhibitor therapy (abciximab) is wise during such a case complicated by intraluminal dissection at a high risk of thrombotic sequela.¹ GP IIb/IIIa inhibitor therapy (abciximab) may also help decrease microvascular injury during prolonged interventional procedures where multiple devices (balloons, stents, IVUS) are being employed to achieve the final result.¹ Based on current data following percutaneous intervention, dual, oral anti-platelet therapy (aspirin and clopidogrel) should be considered for at least one year (perhaps indefinitely) if tolerated by the patient.^2–4 Other adjunctive therapies (statins, ACE inhibitors, etc.) that have beneficial effects on the restenotic process and underlying inflammation should also be considered.⁵ Close clinical follow-up, as noted by the authors, should be a priority due to the diffuse nature of this patient’s disease process and risk of subsequent events within and, importantly, outside the intervened coronary segments. References: 1. Young JJ, Kereiakes DJ. Platelet glycoprotein IIb/IIIa inhibitor use during percutaneous coronary intervention: IIb or not IIb, what is the question? J Invas Cardiol 2002;14:404–410. 2. Mehta SR, Yusuf S, Peters RJ, et al. Effects of pretreatment with clopidogrel and aspirin followed by long-term therapy in patients undergoing percutaneous coronary intervention: the PCI-CURE study. Lancet 2001;358:527–533. 3. Berger PB, Steinhubl S. Clinical implications of percutaneous coronary intervention-clopidogrel in unstable angina to prevent recurrent events (PCI-CURE) study: a US perspective. Circulation 2002;106:2284–2287. 4. Steinhubl SR, Berger PB, Mann JT, et al. Early and sustained dual oral antiplatelet therapy following percutaneous coronary intervention: a randomized controlled trial. J Am Med Assoc 2002;288:2411–2420. 5. Kereiakes DJ. Adjunctive pharmacotherapy before percutaneous coronary intervention in non-ST-elevation acute coronary syndromes: the role of modulating inflammation. Circulation 2003;108(Suppl 1):III22–27. Victor M. Mejia, MD and Joseph R. Carver, MD Cardiovascular Division University of Pennsylvania School of Medicine Philadelphia, Pennsylvania This 69-year-old male presented ten days post-anterior wall myocardial infarction with ongoing recurrent chest pain associated with dynamic anteroseptal ST-T wave changes. We do not know the precipitation or the stability of his symptoms, the degree of LV dysfunction or post event treatment. We assume that he did not have associated carotid or peripheral vascular disease and no additional co-morbidity save Type II diabetes, hypertension and hypercholesterolemia. With these assumptions, we would have proceeded from diagnostic coronary arteriography to bypass surgery (CABG) rather than single or multi-vessel percutaneous coronary intervention (PCI) for total revascularization followed by aggressive management of diabetes, lipids and hypertension. This decision is based on three sets of data. Randomized trials of PCI compared to CABG. EAST, BARI, ARTS trials have consistently demonstrated a benefit of CABG in patients with diabetes for event-free survival (anginal relief, freedom from revascularization) and absolute survival.^1–3 Marso et al.’s Mid-America Heart Institute experience notes an increased early (in-hospital) mortality after both urgent and elective PCI in patients with diabetes compared to patients without diabetes.⁴ The effect is more pronounced for urgent PCI and this patient’s course places him in the urgent category (this is clearly not a mandate to universally deny PCI to patients with diabetes). Equal in importance to target vessel revascularization is the ability to achieve total revascularization to prevent plaque rupture and myocardial infarction in vessels outside the site of the “culprit” vessel. Although generally controversial, this may be a more important factor in patients with diabetes.^5,6 Even assuming the eventual ability to fix all three lesions percutaneously, the bifurcation lesion in the left circumflex has less than favorable anatomy that may preclude successful PCI in this vessel. The clinical utility of IVUS is expanding. IVUS can provide insights into the mechanisms and predictors of restenosis and development of transplant vasculopathy, can help to define optimal stent implantation, and is useful in guiding routine clinical coronary interventions. IVUS can also help define dissections post intervention as studies have shown that angiographically silent edge dissection can occur in 5–23% of stent implantations.⁷ In the reported management of this patient, the post stent appearance of the proximal LAD suggests dissection that required additional stenting. Although this was documented by IVUS, we do not think that IVUS changed the ultimate decision making or procedural approach in this particular angiographically visible lesion. References 1. King SB III, Kosinski AS, Guyton RA, et al. Eight-year mortality in the Emory Angioplasty versus Surgery Trial (EAST). J Am Coll Cardiol 2000;35:1116–1121. 2. Seven-year outcome in the Bypass Angioplasty Revascularization Investigation (BARI) by treatment and diabetic status. J Am Coll Cardiol 2000;35:1122–1129. 3. Serruys PW, Unger F, Sousa JE, et al. Comparison of coronary artery bypass surgery and stenting for the treatment of multivessel disease. N Eng J Med 2001;344:1117–1124. 4. Marso SP, Giorgi LV, Johnson WL, et al. Diabetes mellitus is associated with a shift in the temporal risk profile of in-hospital death after percutaneous coronary intervention: an analysis of 25,223 patients over 20 years. Am Heart J 2003;145:270–277. 5. Deter KM, Lombardi MS, Brooks MM, et al. The effect of previous coronary-artery bypass surgery on the prognosis of patients with diabetes who have acute myocardial infarction. Bypass Angioplasty Revascularization Investigation Investigators. N Engl J Med 2000; 342:989–997. 6. Kuntz RE. The importance of considering atherosclerosis progression when choosing a coronary revascularization strategy: The diabetes-PTCA dilemma. Circulation 1999;23:847–851. 7. Sheri’s SJ, Canoes MJ, Weissman NJ. Natural history of intravascular ultrasound detected edge dissections from coronary stent deployment. Am Heart J 2000; 139(1):59–63.