Management of Acute ST Elevation myocardial infarction

PCI Basics, game plan, avoiding complications are addressed

1. MANAGEMENT OF ACUTE STEMI Dr. N. Praveen MD, DM Associate Professor of Cardiology Osmania General Hospital, Hyderabad From Advanced Interventional Cardiology Tips And Tricks – Thach Nguyen

2. ROADMAP Introduction Checklist Basic principles Game plan Avoiding complications PCI in Special scenarios

3. INTRODUCTION Acute STEMI is usually caused by acute occlusion of a major epicardial coronary artery in the absence of adequate collateral flow from other coronary territories. Aim - Prompt, complete, and sustained recanalization of the infarct-related artery (IRA) with restoration of normal myocardial perfusion, reduces infarct size, preserves left ventricular function, and decreases mortality.

4. CHECK LIST

5. High risk patients In the ER, if patients present with a heart rate(HR) < 100bpm and a blood pressure (BP) >100mm Hg, their in-hospital mortality is very low. Patients with >70 years of age LVEF <45% Multivessel disease Suboptimal PCI Persistent arrhythmia BP <100mm Hg and HR >100 bpm.

6. NEED OF ASSIST A low threshold should be applied for placement of a left ventricular (LV) assist device in hemodynamically unstable patients. If pulmonary edema does not respond quickly to pharmacological treatment, endotracheal intubation and mechanical ventilation is mandatory( intensivist needed).

7. radial approach Highest risk of bleeding (strongly considered). To be avoided in patients with a high likelihood of tortuous subclavian Female gender Advanced age Hypertension Short stature

8. How many arterial and venous access points do we need? Electrical instability (bradycardia ± heart block) – temporary pacemaker – femoral venous access. Cardiogenic shock – two arterial (one to be femoral) and at least one central venous line. To be done simultaneously Having ultrasound equipment ready reduced femoral access times and bleeding rates.

9. PRIMARY PCI WITH NO SURGERY ON SITE Experienced operators who regularly perform elective and primary PCI at tertiary centres. Nursing and technical staff experienced in handling acutely ill patients. Catheterization laboratories are well equipped with resuscitative equipment and LVADs. Staff available 24/7/365 Protocols for emergent transfer to surgical centres (high grade LM, unstable three-vessel disease) Protocols addressing in whom to delay PCI (TIMI 3 flow with <70% residual stenosis).

10. BASIC PRINCIPLES

11. First, the IRA should be determined from a 12-lead ECG. Different views of the presumed non-IRA should be taken with a diagnostic or guide catheter (universal) : assess the extent of disease and collateral flow to distal segments of the IRA. Amplatz L ( to be used as last resort ) ,Tiger, Kimny guide catheters can be used for both. Angiography of the presumed IRA should be performed with a guide so that PCI can be started promptly.

12. The culprit lesion to be characterized in terms of diameter, stenosis, angiographic evidence of thrombus, and epicardial TIMI flow. All the major vessels and their large branches should be accounted for to avoid missing the IRA . There is no need for routine Left ventriculography. If there is a need - extent of LV dysfunction- a pigtail catheter can be inserted.

13. GAME PLAN

14. Guide with adequate coaxial alignment, good support Direct stenting if the IRA opens after passing the wire and distal parts are visualised. Not recommended - tortuous vessels, bifurcations, and complex lesions. Disadvantage - stent undersizing because the distal segment of the IRA may be inadequately filled by contrast due to significant residual stenosis or chronic spasm from prior low flow. Therefore balloon predilation using an undersized balloon (i.e., 2.5 mm) is usually suggested. Actual size and distal diameter of the IRA – intracoronary nitroglycerin (100-200ug) (if not hypotensive).

15. The goal should be a stent: artery ratio of 1:1. Oversizing of the stent edge dissection, distal microvascular embolization, and alpha-adrenergic storm - vasospasm in the distal microvasculature.

16. Complete coverage of the culprit plaque Any residual intimal dissection? Bifurcation lesion with side branch > 2mm – additional wire before stenting (trapped wire technique). If there is plaque shift, significant ostial stenosis or occlusion after stenting the main vessel – exchange of the wire – final KBI Systematic side branch stenting using different techniques such as T, V, Y, Culotte, and crush should be avoided. Does not reduce the rate of restenosis Increases the risk of subacute stent thrombosis.

17. At the end of the procedure, two orthogonal views of the stented segment should be obtained to confirm an optimal angiographic result. Avoid rapid balloon deflation post stent deployment - sudden “vacuum effect” – dislodgement of thrombi.

18. ANGIOGRAPHIC EXCLUSIONS PRECLUDING PERFORMANCE OF PRIMARY PCI Unprotected LM > 60% IRA with stenosis < 70% and with TIMI 3 flow IRA supplies a small area of the myocardium: risk versus benefits Inability to clearly identify the IRA Asymptomatic patients with multivessel disease with TIMI 3 flow, and CABG is indicated.

19. EVALUATION OF THE PCI RESULTS The goal of primary PCI is to achieve successful dilatation of the culprit lesion, normal epicardial blood flow, and adequate microvascular reperfusion of infarcted myocardium. More accurate flow evaluation can be obtained by using the corrected TIMI frame count (CTFC). CTFC is an independent predictor of in-hospital mortality from STEMI and can further stratify patients with TIMI 3 flow into low- and high-risk groups. Restoration of flow in the IRA may not be a reliable predictor of restoration of tissue perfusion supplied by the IRA. TMPG – Risk stratify patients in whom successful epicardial reperfusion was achieved. Very simple bedside indicator of microvascular reperfusion and also early ST segment elevation resolution.

20. AVOIDING COMPLICATIONS

21. AVOIDING VASOVAGAL REACTION Rapid restoration of coronary flow to the IRA supplying the inferior wall of the LV, may lead to profound hypotension and bradyarrhythmias (transient and benign). Aggressively hydrate patients with an inferior STEMI before PCI Avoid administration of nitrates and beta-blockers. If bradycardia and hypotension develop, IV atropine bolus 0.5-1.0 mg, rapid rapid infusion of colloids. Alternatively, IC atropine may be administered (0.1-0.2 mg) - rapid onset of action A femoral venous sheath placed - may be useful for rapid fluid flow and the insertion of a temporary pacemaker if necessary (but this need not be routine). It is also useful to ask conscious patients to perform ‘ cough cardiopulmonary resuscitation ’ to overcome the short period of profound hypotension and bradyarrhythmia.

22. AVOIDING VASOVAGAL REACTION Once the lesion has been crossed, it can be dottered by moving the uninflated balloon back and forth, allowing the flow of stagnant (and possibly acidic blood proximal to the occlusion to seep slowly, instead of flooding, into the distal vasculature. This manoeuvre may decrease the probability of developing reperfusion injury and arrhythmias, especially if the IRA is a large RCA. The manoeuvre may also prevent thrombi embolism due to a sudden strong antegrade flow.

23. BRADYCARDIA Place a temporary wire in the right atrium, ready to advance into the right ventricle for pacing if necessary. In case of a real emergency, we can use the 0.014“ wire in the coronary artery as the pacing wire. If the patient developed VF or VT in the ER or the field, before arrival in CCL, cautious measures – defibrillation patches taped on the chest and back of the patient – reperfusion VT/VF.

24. PCI IN SPECIAL SCENARIOS

25. Primary balloon angioplasty without stenting It is important to remember that not every lesion has to be stented . An optimal angiographic result following POBA (<30% residual stenosis without evidence of dissection/ residual thrombosis and TIMI 3 flow) Wait for 5-10 min - a persistent angiographic result. If there is significant early elastic recoil, dissection, or residual thrombosis is discovered – to be stented. It has to be accepted in patients Excessive proximal tortuosity or calcification that prevents the passage of the stent. IRA of very small diameter (DEB can be used) (STENTLESS PCI) Patients with current bleeding.

26. PCI AFTER THROMBOLYSIS Patients treated with thrombolytic therapy (TT) – delayed access to PCI/ PCI not available. Urgent PCI is indicated 3-4 hours after TT. Rescue PCI - In case of thrombolytic failure, immediate angiography and mechanical recanalization of the IRA remains the treatment of choice. ACC/AHA Taskforce suggests performing urgent angiography in any patients receiving TT with ongoing chest pain or hemodynamic instability, or in asymptomatic patients who are within less than 12 hours of symptom onset with persistent ST elevation after 90 min or TT. It is important to note that patients who required rescue PCI due to failed TT remained at increased risk for occlusion because they had possibly had higher resistance to pharmacological reperfusion, large thrombus burden, or platelet-rich thrombi, factors unfavourable to the performance of mechanical intervention. Rescue PCI should be performed on a high-risk lesion with TIMI ≤ 2.

27. WHERE IS THE IRA ? During the diagnostic angiogram of a patient with STEMI, all arteries and their branches should be thoroughly visualised. Culprit occluded at its ostium – no visible stump for identification Long cine (>100frames) – late retrograde filling of collaterals The presence of other features – wall motion, ECG findings, and any known prior coronary history – that tag the key probable culprits to identify the IRA should be prioritized. Anomalous origin of the coronaries might be the culprit artery. Large diagonal or large OM can be the culprit artery. Deep intubation of the coronaries might miss the dissection of the ostium.

28. TIPS IN CASE OF TOTAL OCCLUDED ARTERY When steering the wire in the RCA, the tip of the wire should point to the outer border of the RCA in the LAO view. In the case of the LAD, the tip should be pointed toward the pericardium and away from the myocardium. How to know where the myocardium is? In the AP cranial, the septals are on the right side of the patient and diagonals are on the left side. The right side is towards the myocardium. The middle is the roof of the LAD. The roof and the left side form the pericardial side of the LAD.

29. Plaques are typically formed on the myocardial side of the LAD and LCX. In the LAD, LCX the tip of the wire needs to be pointed towards the pericardial side of the artery. If the wire goes under a ruptured plaque and a balloon follows the wire and is advanced under the intima, inflation of the balloon would cause dissection of the IRA and distal no flow. Further stenting of the IRA at the lesion area would collapse the IRA distal to the stent and require further stenting in the subintimal plane unless the distal true lumen is re-entered and stented at the reentry site.

30. WHAT TO DO IF THE WIRE CANNOT CROSS THE LESION A small balloon near the distal tip of the wire – strengthens the tip. An exchange microcatheter may be used. Prolong further the door to balloon time and increase the cost of the procedure. An over-the-wire balloon or microcatheter can not only provide enhanced support to the wire but also determine if the wire is in the true lumen upon crossing the stenosis (by small intraluminal injection). Stiffer and hydrophilic wire are usually not required.

31. How to verify that the wire is in the true lumen? After dottering the balloon across the lesion - inject a small amount of contrast to verify that the wire is positioned in the true lumen and not in a side branch. If the wire position is still ambiguous, a small OTW balloon is to be passed. The wire is then removed and contrast can be injected through the central lumen. This manoeuvre also helps in the assessment of artery size for selection of a subsequent balloon or stent.

32. PRIMARY PCI FOR LESIONS WITH THROMBI In situations of small or moderate thrombus burden, conventional PCI should be performed. The thrombotic burden is often large in patients with prolonged symptom duration or if the IRA is a large diameter or ectatic vessel such as an RCA or SVG. Remove the thrombus before stenting to reduce the likelihood of distal embolization in the IRA branches or microcirculation resulting in slow or no reflow phenomenon.

33. Prevention of complications caused by an aspiration device Passes with the aspiration catheter should be made throughout the thrombus length until there is no angiographic evidence of thrombus on repeat angiogram. In case of a large thrombus - thrombotic material can clog the aspiration holes halting aspiration. Remove the catheter, flush it profusely, and re-advance it for a few more passes. Attention to be paid to the movement of the tip of the wire ( they are not perfect monorail catheters). If the tip stands still while the catheter is advanced, the aspiration catheter may bend the wire, form a sticking point, and dissect or perforate the artery. The guide must be immediately and generously aspirated as the aspiration catheter could drag the tail of a long thread thrombus that may get dislodged and embolize into the guide.

34. SLOW FLOW NO REFLOW Diminished epicardial blood flow despite a widely patent IRA, known as the slow reflow or no-reflow phenomenon is due to compromised distal microvascular perfusion. The mechanism is probably heterogeneous Thrombus –plaque microvascular embolization with subsequent platelet activation Release of potent vasoconstrictors and Microvascular spasm. Flow will most likely improve after infusion of adenosine, nicorandil, calcium channel blockers, or nitroprusside.

35. If flow still cannot be established, plugging of the microvascular bed (‘no reflow’) may have occurred and require distal delivery of arterial dilators such as adenosine, nitroprusside, or nicardipine. Through the lumen of the aspiration catheter under gentle flush – drug delivery is more precise and targeted. If no reflow persists despite exhausting these options, blood may be aspirated and forced back into the coronary using a 10-20ml syringe in an attempt to unplug the microvasculature; this technique should be a last resort as it risks distal air/thrombus embolization.

36. PERSISTENT THROMBOTIC BURDEN After POBA – thrombus present - Check the wire to be sure that it is inside the main lumen. Angiojet or X-sizer device Pronto or export catheter Residual thrombus – intracoronary rTPA – 5 mg boluses down the LCA via the guide every 5 minutes.( upto 50 mg) Vessel is good and clear of thrombus – IV heparin over the next 24 hours should be continued (ACT >200sec). Distal coronary flow is suboptimal – abciximab IC – IV infusion. Tirofiban used more frequently here.

37. PCI FOR PATIENTS WITH CARDIOGENIC SHOCK After angiography – the decision to proceed with intervention or placement of LVAD is to be considered. Initial intervention of an LM occlusion should not be attempted until the support device has been initiated. Provides essential backup cardiac output. Assessment of patients’ femoral and iliac vessels first. Severe PAD not amenable to a quick balloon angioplasty will preclude the use of most devices. An impella CP – most rapid, reliable cardiac output on average compared to IABP,ECMO or Tandemheart .

38. PCI OF LEFT MAIN If survived to cathlab – intermittent occlusion, a very dominant and patent RCA, or an anomalous origin of LCA. Profund cardiogenic shock – concomitant LVAD, Vasopressors, inotropes, mechanical ventilation should be started. iRA vs concomitant disease. CABG Guide as aspiration device

39. PCI IN RIGHT VENTRICULAR INFARCTION Although uncommon, it can occur when a non-dominant or co-dominant RCA proximal to an acute marginal branch or an acute marginal branch itself is occluded. An isolated RVI may occur secondarily to an acute occlusion of the RV branch following PCI. The coexistence of RVI with severe LV hypertrophy probably favours the appearance of hemodynamic manifestations in two ways. 1, LV diastolic dysfunction may produce an increase in PCWP and thus facilitate the occurrence of RV failure. 2, The decreased LV preload due to RVI may be potentially more serious in the presence of LV diastolic dysfunction.

40. PCI of SAPHENOUS VENOUS GRAFT STEMI in patients with a prior history of CABG, usually related to SVG rather than mammary artery occlusion, affects smaller territories and presents with milder symptoms. There is a significant risk of distal embolization and slow or noreflow phenomenon because of the large size of the SVG and high thrombotic burden. PCI of the native coronary artery supplied by the graft should be attempted first if the likelihood of success is realistic. If not, the PCI of SVG to be attempted. Distal protection device should be used if the culprit artery lesion allows. If a large thrombotic burden is identified, DPD should be combined with thrombotic aspiration

41. PCI FOR STEMI PATIENTS WITH CURRENT BLEEDING In general, the principle is that PCI can be performed if the bleeding can be stopped by mechanical means (compressing or ligating the artery) and the patient can tolerate 4 hours of anticoagulant without excessive further bleeding during PCI. Anticoagulant - UFH - short half-life, it can be reversed by protamine. On going intracranial, lower intestinal, or esophageal variceal bleeding is the only contraindication for primary PCI. Size of CFV = CFA SAPT Balloon angioplasty

42. TAKE HOME MESSAGE 1. One arterial and two venous access are important in an unstable patient with STEMI. 2. Adequate hydration and low threshold for placement of TPI in a patient with inferior wall MI and RV MI. 3. Pulmonary edema not responding to pharmacological management – elective intubation. 4. Direct stenting will lead to undersizing . 5. Adequate nitroglycerin to be given for assessment of distal vessel before stenting. 6. Ostial occlusion of branches can be missed – detailed review before coming out. 7. Left main intervention to be done staged after addressing the culprit artery. 8. Rapid deflation of the balloon after deployment of stent to be avoided. 9. Dottering of the thrombotic lesion to be done before deployment of the stent. 10. POBA without stenting is a valid option in selective cases.

43. Finally to conclude…. Aim of a primary PCI aim is TIMI III Flow, it is not the placement of the stent. The procedure has to be kept simple, not complicated. A complication will lead to further complications in primary PCI. Always call for help when there is a complication. Aiming for perfection in primary PCI will land us in trouble. Primary PCI is a team approach. THANK YOU