STEMI vs NSTEMI Treatment: Protocols, PCI and Recovery

STEMI and NSTEMI treatment runs at opposite tempos. In STEMI the artery is completely blocked, so the patient goes straight to the catheterisation laboratory, or receives thrombolysis where that is not possible, without waiting for blood tests. In NSTEMI and unstable angina the artery is not presumed to be fully occluded, so patients are stabilised on antiplatelets first and undergo angiography early only if pain continues or they deteriorate.

That contrast was the centre of the management guidance in the Jivo Masterclass by Dr. Vikas Thakran, Consultant, Interventional Cardiology, BLK-Max Super Speciality Hospital, New Delhi, India, at the time of the masterclass. This article sets out both protocols, the drugs used in the first hour, how angioplasty is performed and when bypass is chosen instead, the complications of the procedure, the management of dangerous heart rhythms, and nutrition and recovery after the event. The mechanism and symptoms of acute coronary syndrome are in the complete guide to acute coronary syndrome, and the ECG patterns that decide between the two pathways are in the article on STEMI, NSTEMI and ECG localisation.

STEMI vs NSTEMI treatment: the two protocols side by side

The difference between STEMI and NSTEMI treatment follows from how fully the artery is presumed to be blocked, and therefore how fast it must be opened.

STEMI treatment protocol: do not wait

Dr. Thakran's instruction for STEMI was unambiguous: do not wait for investigations. A single ECG showing ST elevation is good enough. The immediate steps he listed were:

1. Relieve pain with intravenous opioids.
2. Give a sublingual nitrate to relieve the ischaemic pain (with the caution in inferior wall infarction described below).
3. Give oxygen.
4. Give antiplatelets.
5. Open the artery.

Opening the artery is the treatment; everything else supports it. Percutaneous coronary intervention (PCI), in which the blocked artery is reopened with a balloon and a stent through a catheter, is in his words the gold standard and the procedure that saves the life. Where PCI is not possible, fibrinolytic therapy (thrombolysis) is given: a clot-dissolving drug administered intravenously, used at centres without access to stenting. Rarely, an emergency bypass operation is needed, but he described that as a very rare scenario.

On oxygen, current guidelines are more selective than routine use: they recommend supplemental oxygen when blood oxygen saturation is below 90%, and not routinely in patients whose saturation is normal.

On timing, Dr. Thakran said it is very important to treat within the first two hours. International guidelines set the same benchmark from the other direction: if PCI cannot be delivered within 120 minutes of the diagnosis, thrombolysis should be given instead. The choice between the two strategies, and the thrombolytic drugs themselves, are covered in depth in Dr. Rohit Goel's article on thrombolysis vs primary angioplasty for STEMI.

Nitrates in a heart attack: the inferior wall exception

Sublingual nitrate is the nitrate of choice in a heart attack, except in inferior wall STEMI, where Dr. Thakran cautioned that it may not be good management. An attendee from Ghana asked him when nitrates should be given and which preparation is best, and his answer set out a clear hierarchy:

• Sublingual nitrate is the therapy of choice, because it acts quickly. The sublingual preparation used in his setting, isosorbide dinitrate, is widely available.
• If the patient does not get relief, an intravenous infusion of nitroglycerin can be given, together with opioids in cases of extreme pain.
• Care is needed in inferior wall STEMI. In those patients, he said, nitrates may not be good management. In his summary: sublingual nitrate is the treatment except when the patient has a right-sided artery STEMI.

The reason for the exception is physiological. An inferior infarction usually results from an occluded right coronary artery, which often also supplies the right ventricle. A right ventricle damaged in this way depends on adequate venous filling to maintain output, and nitrates, which dilate the veins and reduce that filling, can cause a sharp fall in blood pressure. Nitrates are also avoided when the systolic blood pressure is low and in patients who have recently taken a phosphodiesterase-5 inhibitor for erectile dysfunction.

NSTEMI treatment protocol: stabilise, then angiography

NSTEMI and unstable angina are treated by stabilising the patient on antiplatelets first and then performing angiography, an X-ray of the coronary arteries using contrast dye. Dr. Thakran's approach was deliberately measured, with angiography on one of two timelines:

• Early, within the first two days, for patients who continue to have pain or who deteriorate.
• After two days of antiplatelet treatment, for patients managed as low risk.

He explained the reasoning from experience: these patients do well with this slower antiplatelet-based management, and taking them directly to the laboratory is not as beneficial.

International guidelines stratify the timing more finely by risk. Patients with very high-risk features, such as haemodynamic instability, recurrent or refractory chest pain or life-threatening arrhythmias, are recommended an immediate invasive strategy within two hours; angiography within 24 hours should be considered for patients with a confirmed NSTEMI or other high-risk features; and lower-risk patients undergo a selective invasive strategy.

How angioplasty (PCI) is performed, step by step

Angioplasty is performed in five steps through an artery at the wrist or the groin: access, angiography, wire, balloon and stent. Asked how a PCI is performed, Dr. Thakran described the sequence:

1. Access. The cardiologist enters the arterial system through one of two routes: the radial artery at the wrist or the femoral artery in the groin.
2. Angiography. Catheters placed through that artery are used to inject contrast into the coronary arteries and locate the blockages. The team then forms a treatment plan.
3. Wire. A fine guide wire is passed across the blockage.
4. Balloon. A balloon is advanced over the wire and inflated to open the narrowing.
5. Stent. A stent, a small mesh tube, is placed to hold the artery open.

In an acute heart attack, he added, PCI directly clears the thrombus, places a stent and restores flow. The radial route is now the default in most centres, because it causes fewer bleeding complications than femoral access. Indicative costs are on the angioplasty with stent cost page.

When bypass surgery is better than a stent

Not every blockage should be stented. When there are multiple complex blockages that would require too many stents, Dr. Thakran advised coronary artery bypass grafting (CABG) instead, depending on the patient's profile. At his centre the decision belonged to a heart team: after angiography, the interventional cardiologists and the cardiothoracic surgeons discussed each patient together and chose stenting or bypass jointly.

The surgeons there had experience of total arterial bypass, in which the grafts are taken from arteries in the chest, the internal thoracic (internal mammary) arteries, rather than from veins in the legs. Arterial grafts are preferred because they remain open longer than vein grafts. Costs for surgery are on the coronary artery bypass graft cost page, and the evidence on stent versus bypass in multivessel and left main disease is examined in Dr. Biswarup Purkayastha's article on left main coronary artery disease treatment.

Treating complex and calcified coronary disease

Dr. Thakran described the techniques his centre used for complex anatomy:

• Left main and bifurcation angioplasty, for blockages in the main trunk of the left coronary system and at points where an artery divides.
• Rotablation (rotational atherectomy), in which a diamond-coated burr spinning at high speed grinds away heavily calcified plaque so a balloon and stent can expand.
• Intracoronary lithotripsy, in which a balloon catheter emits sonic pressure waves that fracture calcium within the artery wall.
• Mechanical circulatory support for critically ill patients with very low blood pressure: the Impella, a small pump placed across the aortic valve that moves blood from the left ventricle into the aorta, and the intra-aortic balloon pump (IABP), a balloon in the aorta that inflates between heartbeats to improve coronary flow and reduce the heart's workload.

Angioplasty complications: how safe is the procedure?

Angioplasty is roughly 95 to 98% safe, in Dr. Thakran's estimate, and the complications he described fall into two groups:

• Access-site complications: bleeding from the wrist or groin puncture.
• Coronary complications: stent thrombosis, in which a clot forms inside the new stent and blocks it, and, rarely in very difficult vessels, perforation of the coronary artery.

In extreme cases, he added, the procedure can be fatal, but these complications are rare. Set against the 30 to 50% mortality he cited for an untreated heart attack, and the fall to around 5% with treatment, the balance of risk is decisive.

Defibrillation and ICDs after a heart attack

Ventricular tachycardia and ventricular fibrillation are the rhythms that kill in the acute phase. Dr. Thakran described two distinct roles for defibrillation:

• Acute event: an external defibrillator is used for ventricular tachycardia or ventricular fibrillation, whether at presentation, during the procedure or after it.
• Follow-up: patients left with poor heart function, a low ejection fraction, may receive an implantable cardioverter-defibrillator (ICD), a device implanted like a pacemaker that detects these rhythms and shocks the heart back into a normal rhythm.

Guidelines generally reassess heart function some weeks after the infarction before recommending an ICD, because the ejection fraction often recovers once the artery has been opened.

Recovery after angioplasty: diet and early discharge

Recovery after PCI is fast. In Dr. Thakran's setting, patients admitted with a heart attack could be discharged within 36 hours of the procedure.

On nutrition, Dr. Thakran distinguished the acute event from the long term. Because acute coronary syndrome is a sudden event, nutrition in the first days is largely decided by the patient's hydration status. A patient who presents late with severe breathlessness, a sign that the heart is failing, is given a low-salt diet, and intravenous fluids and overhydration are avoided. For the long term, high-fat and deep-fried foods should be avoided to keep cholesterol down.

At his hospital, policy was that every patient received a dietician consultation, so that diet was tailored to each patient's ejection fraction and risk factors; he described that support as of paramount importance.

Heart transplant and advanced heart failure

Medical and interventional therapies now delay or avoid transplantation for many patients with heart failure, although worldwide demand for donor hearts still exceeds supply. Asked how many transplants his centre performed, Dr. Thakran noted that donor availability and cost remain obstacles. The number at his centre was two or three a year, with the facility and an in-house left ventricular assist device (LVAD) programme available for the extreme cases that need them. Device and transplant options in advanced heart failure are covered in Dr. Rajpal Singh's article on when to refer for ICD, CRT, LVAD or transplant.

Wider cardiac services and international transfer

Beyond coronary disease, Dr. Thakran described the broader cardiac services at BLK-Max at the time: structural heart intervention including transcatheter aortic valve implantation (TAVI); an electrophysiology unit implanting pacemakers and ICDs and performing complex ablations with 3D mapping; peripheral interventions including neurovascular and carotid procedures; device closure of congenital defects such as atrial septal defect, ventricular septal defect and patent ductus arteriosus; and paediatric cardiac surgery for both cyanotic and acyanotic congenital heart disease, in a hospital of around 650 beds in central Delhi.

For a critically ill patient abroad, such as one with an anterior wall infarction who has collapsed, the transfer was organised by the hospital's international team. That team handled every step from the visa process to the transfer itself, with ambulances at the airport, and looked after the family during their stay. It first collected the patient's details and then consulted the cardiologists on the right course of action.

The doctors' questions on evacuation, PCI technique, transplant numbers, nitrates, nutrition and defibrillation are answered in full in the session's Live Discussion, and Dr. Thakran's background is on his doctor profile. More heart care content is on the cardiology specialty page.