Percutaneous coronary intervention
Percutaneous coronary intervention (PCI) involves procedures on coronary arteries via catheters introduced via peripheral arteries. These are usually:
- Angioplasty - see also primary angioplasty after myocardial infarction.
- A stent insertion is commonly inserted following angioplasty.
The techniques are widely used and have been refined as a result of multiple clinical trials. Essentially they are either done acutely at primary presentation (primary PCI) of acute coronary syndrome, semi-electively shortly after a presentation with an acute myocardial infarction or electively in the management of coronary artery disease. While like any technique there will be a degree of operator dependence and preference some generalisations are possible and the risks and benefits compared to alternative management strategies are reasonably well understood. We know that in primary PCI, that while the choice of femoral or radial route of initial arterial access makes no significant difference to mortality, incidence of myocardial infarction or stroke, radial access has a lower rate of local vascular complications and is likely to increasingly replace femoral access. The major risk factors for adverse outcome are age and prior general and neurological conditions, particularly cerebrovascular events . Interestingly emergency presentations are more clearly associated with adverse outcomes in the elderly than elective procedures and this may partially reflect better opportunities for evaluating procedure risk in the later group resulting in case selection.
Stable coronary artery disease
It is known that optimal medical therapy alone is as efficacious in terms of the outcomes of death and myocardial infarction as optimal medical therapy and percutaneous coronary intervention (PCI) for treatment of patients with stable coronary artery disease. In the case of PCI determined by fractional flow reserve (FFR) at angiographically demonstrated lesions in stable coronary artery disease there is a highly significant reduction in the need for urgent revascularisation compared to best medical therapy.
In the case of myocardial infarction primary percutaneous coronary intervention (primary PCI) is probably economically justifiable in societies with good transport infrastructure and organisation of acute health services, if it can be done within 90 minutes of presentation when the alternative is thrombolysis. Thrombolysis can be combined with late PCI in the window 1 to 3 hours for superior outcome in ST elevation myocardial infarction. There is good evidence for clinical benefit of PCI within 6 hours of thrombolysis in high risk patients  from the TRANSFER-AMI trialand fair clinical risk-benefit stratification is possible from meta-analysis.
There has been controversy as to the benefit of thrombus aspiration at primary PCI resolved to no net favour due to risk of stroke with primary outcome being very similar. Earlier work such as the TAPAs study had suggested that up to one year in ST-elevation myocardial infarction treated with PCI and stenting  an absolute benefit in terms of one year mortality of just over 3%.
Optimal and safe primary PCI depends upon optimal choice of antiplatelet and anticoagulant before, during and after the procedure. A large literature exists and optimal regimes have been defined for many combinations of individual circumstances and interventions such as stents. Specialist guidelines exist and both patients and their non cardiological doctors need to understand some of the issues involved, such as non compliance, with its risk of stent thrombosis. Some very complex regimes designed for example to maximise anticoagulation with its risk of bleeding for the minimal possible time have failed, often due to unforeseen properties of the product such as its antigenicity.
Coronary artery stents were historically either bare metal or drug-eluting. Bioresorbable vascular scaffolds have become the third main stream technology. Drug-eluting stents have evolved into the standard of care but their rigid walls do not reproduce the plasticity of biological vessels and neo-atherosclerosis can still occur leading to stent thrombosis and repeat vascularisation. The relative merits of the three (and different drugs that are eluted) are currently subject to controversy with financial implications. The drug eluting ones are less likely to re-occlude than the plain ones in the long term, but until the endothelium has regrown over them - the process the eluted drugs retard - they are more prone to clotting and occluding.. Very early target vessel failure seems slightly more common with bioresorbable vascular scaffolds but over 30 months both have a failure rate of 10%. With current drug thromboprophylaxis strategies (they do differ depending upon the stent!) scaffolds based on everolimus elution have a 2% rate of device thrombosis at 30 months versus less than 1% rate in everolimus eluting metallic stent.
- Mortality rates
- Myocardial infarction
- Repeat revascularization
- Those with diabetes and more than 2 vessel disease
Much of the benefit seems to be in reduced long term complication rate and in selected subgroups such as those with severe left ventricular dysfunction drug-eluting stents are likely to offer better outcome
Dual antiplatelet therapy
At the time of stent insertion, particularly with primary PCI the patient is likely to have a special, probably triple therapy loading regime.
Stent occlusion is opposed by aspirin and a thienopyridine which it is very important to continue for a suitable period, currently given as 6 months to a year for the drug eluting stent, and notably shorter for the plain metal one. If you run into bleeding issues, try not to stop antiplatelet therapy and if you do have to stop it, only the cardiologist is likely to be able to estimate accurately the risk of so doing in terms of stent thrombosis, as it will be a stent specific function of time since implantation.
The combination of aspirin and clopidogrel may be accompanied by bruising, sometimes impressive (particularly if it is sub-conjunctival), but ceasing treatment is a serious decision to be made only with the utmost caution.
Risk benefit of continuing dual antiplatelet therapy
This is an individualised assessment but has an evidence base. The DAPT prediction rule is a score, ranging from −2 to 10 that may help inform clinicians of the relative balance in benefit and harm of dual antiplatelet therapy beyond 1 year following percutaneous coronary intervention.
|Younger than 65 years||0|
|Age 65 to 75 years||-1|
|Age 75 years or older||-2||In elderly risk of bleeding on anti-platelets tends to out weigh benefits|
|Vein graft stent||2||Patients whose vein grafts secondary stenose are high risk of myocardial infarction|
|Smoking within past year||1|
|Myocardial infarction at presentation||1||ACS patient proceeding to PCI more likely to benefit from prolonged dual platelet therapy|
|History of CHF or left ventricular ejection fraction lower than 30%,||2||Disabled heart very likely to benefit from prolonged dual platelet therapy|
|Stent diameter less than 3 mm||1||Small stents increase relative benefit from antiplatelet agents|
|Paclitaxel-eluting stent||1||Antiplatet therapy more important in paclitaxel-eluting stents|
Combined antiplatelet and anticoagulation therapy
This is likely to be indicated in acute coronary syndrome when the patient is already on anticoagulation for another indication at the time of presentation. ESC consensus guidelines exist and have evolved (latest guideline at https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines) into ever greater use of DOAC (NOAC)s at expense of warfarin and the use only of aspirin and clopidogrel rather than other antiplatelet agents. The trade offs had lead to the resources necessary in very tight warfarin control but now reduced dose DOACs are being tried. Essentially in patients at low to moderate bleeding risk, and a good indication anticoagulation (warfarin) is continued with the antiplatelet agents covering the highest risk period of stent thrombosis. Thus elective metal stents get 1 month of triple therapy, elective 'olimus coated stents get 3 months triple therapy and to 12 months an antiplatelet and anticoagulant, while elective paclitaxel coated stents get 6 months triple therapy, then up to 12 months an antiplatelet and anticoagulant. This last regime also applies to all stents used in primary PCI. If risk of haemorrhage is high use bare metal stents in all indications and up to 4 weeks of triple therapy, then in elective patients revert to warfarin but in primary PCI ACS patients give 6 months antiplatelet and anticoagulant before reverting to anticoagulation alone.
The intensive analysis of the clinical trial data suggests:
- Diabetic patients and those with acute coronary syndrome may be better off with a bare metal stent
- The extensive take up of drug eluting stents based on short term studies showing benefit for easily measured primary cardiac outcome measures rather than awaiting total mortality and cardiac event rates over several years was premature. Not all drug eluting stents are equivalent and indeed the drug of choice is definitely evolving.
- Patients need to be selected for stent type and this selection needs to consider multiple patient parameters, the cost of the therapy and cost and convenience of long term drug prophylaxis.
- In patients with stable coronary artery disease on optimal medical therapy of antiplatelet agent, betablockers, calcium channel blockers, nitrates, ACE inhibitors (or proven Angiotensin II inhibitors) and statins the COURAGE trial has confirmed previous studies that the addition of percutaneous coronary intervention (PCI) with stents:
- reduction myocardial infarction and death is unlikely to be benefical
- symptom control of angina is likely to be beneficial for the first 3 years but unlikely to be benefical after this with PCI
- Early stent thrombosis after PCI is associated with:
- The risk of plain stent thrombosis is associated with:
- Discontinuing clopidogrel therapy
- First 30 days after the index PCI hazard ratio = 36 (8 - 168)
- 30 days to 6 months after the index PCI hazard ratio = 4.6 (1.4 - 15.3)
- Beyond 6 months hazard ratio = 5.9 (1.7 to 19.8)
- Undersizing of the coronary stent
- Poor flow through stent and other technical issues like lesion at arterial bifurcation
- Concurrent malignancy
- Coronary artery disease proximal and distal to the stent
- No aspirin
- Ejection fraction <30%
- Younger age
- Discontinuing clopidogrel therapy
- The risk of drug-eluting stent thrombosis is associated with:
- Premature antiplatelet therapy discontinuation
- Renal failure
- Lower ejection fraction
- Acute coronary syndrome at presentation
- Diabetes mellitus
- Few doctors, including most cardiologists would have the time to navigate the massive amount of information published in the last few years and translate it into advice that is objective and not subject to selection or other bias.
- ↑ Jolly SS, Yusuf S, Cairns J, Niemelä K, Xavier D, Widimsky P, Budaj A, Niemelä M, Valentin V, Lewis BS, Avezum A, Steg PG, Rao SV, Gao P, Afzal R, Joyner CD, Chrolavicius S, Mehta SR. Radial versus femoral access for coronary angiography and intervention in patients with acute coronary syndromes (RIVAL): a randomised, parallel group, multicentre trial. Lancet. 2011 Apr 4.(Epub ahead of print) (Link to article – subscription may be required.)
- ↑ Hoffman SJ, Holmes DR, Rabinstein AA, Rihal CS, Gersh BJ, Lennon RJ, Bashir R, Gulati R. Trends, Predictors, and Outcomes of Cerebrovascular Events Related to Percutaneous Coronary Intervention A 16-Year Single-Center Experience. JACC. Cardiovascular interventions. 2011 Apr; 4(4):415-422.(Link to article – subscription may be required.)
- ↑ Schwarz AK, Zahn R, Hochadel M, Kerber S, Hauptmann KE, Glunz HG, Mudra H, Darius H, Zeymer U. Age-related differences in antithrombotic therapy, success rate and in-hospital mortality in patients undergoing percutaneous coronary intervention : Results of the quality control registry of the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte (ALKK). Clinical research in cardiology : official journal of the German Cardiac Society. 2011 Apr 21.(Epub ahead of print) (Link to article – subscription may be required.)
- ↑ Holper EM, Addo T. Clinical implications of the BARI 2D and COURAGE trials: the evolving role of percutaneous coronary intervention. Coronary artery disease. 2010 Nov; 21(7):397-401.(Link to article – subscription may be required.)
- ↑ De Bruyne B, Pijls NH, Kalesan B, Barbato E, Tonino PA, Piroth Z, Jagic N, Mobius-Winckler S, Rioufol G, Witt N, Kala P, Maccarthy P, Engström T, Oldroyd KG, Mavromatis K, Manoharan G, Verlee P, Frobert O, Curzen N, Johnson JB, Jüni P, Fearon WF. Fractional Flow Reserve-Guided PCI versus Medical Therapy in Stable Coronary Disease. The New England journal of medicine. 2012 Aug 27.(Epub ahead of print) (Link to article – subscription may be required.)
- ↑ Vergel1 YB, Palmer S, Asseburg C, Fenwick E, de Belder M, Abrams K, Sculpher M. Is primary angioplasty cost effective in the UK? Results of a comprehensive decision analysis. Heart 2007;93:1238-1243 link to full article (subscription may be required)
- ↑ Armstrong PW, Gershlick AH, Goldstein P, Wilcox R, Danays T, Lambert Y, Sulimov V, Ortiz FR, Ostojic M, Welsh RC, Carvalho AC, Nanas J, Arntz HR, Halvorsen S, Huber K, Grajek S, Fresco C, Bluhmki E, Regelin A, Vandenberghe K, Bogaerts K, Van de Werf F. Fibrinolysis or Primary PCI in ST-Segment Elevation Myocardial Infarction. The New England journal of medicine. 2013 Mar 10.(Epub ahead of print) (Link to article – subscription may be required.)
- ↑ Cantor WJ, Fitchett D, Borgundvaag B, Ducas J, Heffernan M, Cohen EA, Morrison LJ, Langer A, Dzavik V, Mehta SR, Lazzam C, Schwartz B, Casanova A, Goodman SG. Routine early angioplasty after fibrinolysis for acute myocardial infarction. The New England journal of medicine. 2009 Jun 25; 360(26):2705-18.(Link to article – subscription may be required.)
- ↑ Cantor WJ, Fitchett D, Borgundvaag B, Heffernan M, Cohen EA, Morrison LJ, Ducas J, Langer A, Mehta S, Lazzam C, Schwartz B, Dzavik V, Goodman SG. Rationale and design of the Trial of Routine ANgioplasty and Stenting After Fibrinolysis to Enhance Reperfusion in Acute Myocardial Infarction (TRANSFER-AMI). American heart journal. 2008 Jan; 155(1):19-25.(Link to article – subscription may be required.)
- ↑ De Luca G, Cassetti E, Marino P. Percutaneous coronary intervention-related time delay, patient's risk profile, and survival benefits of primary angioplasty vs lytic therapy in ST-segment elevation myocardial infarction. The American journal of emergency medicine. 2009 Jul; 27(6):712-9.(Link to article – subscription may be required.)
- ↑ Jolly SS, Cairns JA, Yusuf S, Meeks B, Pogue J, Rokoss MJ, Kedev S, Thabane L, Stankovic G, Moreno R, Gershlick A, Chowdhary S, Lavi S, Niemelä K, Steg PG, Bernat I, Xu Y, Cantor WJ, Overgaard CB, Naber CK, Cheema AN, Welsh RC, Bertrand OF, Avezum A, Bhindi R, Pancholy S, Rao SV, Natarajan MK, ten Berg JM, Shestakovska O, Gao P, Widimsky P, Džavík V. Randomized trial of primary PCI with or without routine manual thrombectomy. The New England journal of medicine. 2015 Apr 9; 372(15):1389-98.(Link to article – subscription may be required.)
- ↑ Härle T, Zeymer U, Hochadel M, Schmidt K, Zahn R, Darius H, Behrens S, Lauer B, Mudra H, Schächinger V, Elsässer A. Use and impact of thrombectomy in primary percutaneous coronary intervention for acute myocardial infarction with persistent ST-segment elevation: results of the prospective ALKK PCI-registry. Clinical research in cardiology : official journal of the German Cardiac Society. 2015 Mar 25.(Epub ahead of print) (Link to article – subscription may be required.)
- ↑ Svilaas T, van der Horst IC, Zijlstra F. Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS)--study design. American heart journal. 2006 Mar; 151(3):597.e1-597.e7.(Link to article – subscription may be required.)
- ↑ Vlaar PJ, Svilaas T, van der Horst IC, Diercks GF, Fokkema ML, de Smet BJ, van den Heuvel AF, Anthonio RL, Jessurun GA, Tan ES, Suurmeijer AJ, Zijlstra F. Cardiac death and reinfarction after 1 year in the Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS): a 1-year follow-up study. Lancet. 2008 Jun 7; 371(9628):1915-20.(Link to article – subscription may be required.)
- ↑ Lincoff AM, Mehran R, Povsic TJ, Zelenkofske SL, Huang Z, Armstrong PW, Steg PG, Bode C, Cohen MG, Buller C, Laanmets P, Valgimigli M, Marandi T, Fridrich V, Cantor WJ, Merkely B, Lopez-Sendon J, Cornel JH, Kasprzak JD, Aschermann M, Guetta V, Morais J, Sinnaeve PR, Huber K, Stables R, Sellers MA, Borgman M, Glenn L, Levinson AI, Lopes RD, Hasselblad V, Becker RC, Alexander JH. Effect of the REG1 anticoagulation system versus bivalirudin on outcomes after percutaneous coronary intervention (REGULATE-PCI): a randomised clinical trial. Lancet (London, England). 2015 Nov 4.(Epub ahead of print) (Link to article – subscription may be required.)
- ↑ Kostis WJ, Demissie K, Marcella SW, Shao YH, Wilson AC, Moreyra AE; Myocardial Infarction Data Acquisition System (MIDAS 10) Study Group.Weekend versus weekday admission and mortality from myocardial infarction. N Engl J Med. 2007;356(11):1099-109
- ↑ Ejiri K, Ishihara M, Dai K, Miki T, Inoue I, Kawagoe T, Shimatani Y, Miura F, Nakama Y, Otani T, Ikenaga H, Oda N, Nakamura M. Three-Year Follow-up of Sirolimus-Eluting Stents vs. Bare Metal Stents for Acute Myocardial Infarction. Circulation journal : official journal of the Japanese Circulation Society. 2011 Oct 29.(Epub ahead of print)
- ↑ Shuchman M. Trading restenosis for thrombosis? New questions about drug-eluting stents. The New England journal of medicine 2006;355:1949-52. (Direct link – subscription may be required.)
- ↑ Maisel WH. Unanswered Questions - Drug-Eluting Stents and the Risk of Late Thrombosis. N Eng J Med 2007 356;10:981-984
- ↑ Wykrzykowska JJ, Kraak RP, Hofma SH, van der Schaaf RJ, Arkenbout EK, IJsselmuiden AJ, Elias J, van Dongen IM, Tijssen RY, Koch KT, Baan J, Vis MM, de Winter RJ, Piek JJ, Tijssen JG, Henriques JP. Bioresorbable Scaffolds versus Metallic Stents in Routine PCI. The New England journal of medicine. 2017 Mar.(Print-Electronic) (Link to article – subscription may be required.)
- ↑ Hannan EL, Racz MJ, Walford G, Jones RH, Ryan TJ, Bennett E, Culliford AT, Isom OW, Gold JP, Rose EA. Long-term outcomes of coronary-artery bypass grafting versus stent implantation. The New England journal of medicine. 2005 May 26; 352(21):2174-83.(Link to article – subscription may be required.)
- ↑ Hannan EL, Wu C, Walford G, Culliford AT, Gold JP, Smith CR, Higgins RS, Carlson RE, Jones RH. Drug-eluting stents vs. coronary-artery bypass grafting in multivessel coronary disease. The New England journal of medicine. 2008 Jan 24; 358(4):331-41.(Link to article – subscription may be required.)
- ↑ Javaid A, Steinberg DH, Buch AN, Corso PJ, Boyce SW, Pinto Slottow TL, Roy PK, Hill P, Okabe T, Torguson R, Smith KA, Xue Z, Gevorkian N, Suddath WO, Kent KM, Satler LF, Pichard AD, Waksman R. Outcomes of coronary artery bypass grafting versus percutaneous coronary intervention with drug-eluting stents for patients with multivessel coronary artery disease. Circulation. 2007 Sep 11; 116(11 Suppl):I200-6.(Link to article – subscription may be required.)
- ↑ Yang JH, Gwon HC, Cho SJ, Hahn JY, Choi JH, Choi SH, Lee YT, Lee SH, Hong KP, Park JE. Comparison of coronary artery bypass grafting with drug-eluting stent implantation for the treatment of multivessel coronary artery disease. The Annals of thoracic surgery. 2008 Jan; 85(1):65-70.(Link to article – subscription may be required.)
- ↑ Gioia G, Matthai W, Gillin K, Dralle J, Benassi A, Gioia MF, White J. Revascularization in severe left ventricular dysfunction: outcome comparison of drug-eluting stent implantation versus coronary artery by-pass grafting. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions. 2007 Jul 1; 70(1):26-33.(Link to article – subscription may be required.)
- ↑ Yeh RW, Secemsky EA, Kereiakes DJ, Normand ST, Gershlick AH, Cohen DJ, Spertus JA, Steg PG, Cutlip DE, Rinaldi MJ, Camenzind E, Wijns W, Apruzzese PK, Song Y, Massaro JM, Mauri L. Development and Validation of a Prediction Rule for Benefit and Harm of Dual Antiplatelet Therapy Beyond 1 Year After Percutaneous Coronary Intervention. JAMA. 2016 Mar 29.(Epub ahead of print) (Link to article – subscription may be required.)
- ↑ Lip GY, Huber K, Andreotti F, Arnesen H, Airaksinen KJ, Cuisset T, Kirchhof P, Marín F. Management of antithrombotic therapy in atrial fibrillation patients presenting with acute coronary syndrome and/or undergoing percutaneous coronary intervention/ stenting. Thrombosis and haemostasis. 2010 Jan; 103(1):13-28.(Link to article – subscription may be required.)
- ↑ Daemen J, Wenaweser P, Tsuchida K, Abrecht L, Vaina S, Morger C, et al. Early and late coronary stent thrombosis of sirolimus-eluting and paclitaxel-eluting stents in routine clinical practice: data from a large two-institutional cohort study. Lancet 2007;369:667-78. (Direct link – subscription may be required.)
- ↑ Spaulding C, Daemen J, Boersma E, Cutlip DE, Serruys PW. A Pooled Analysis of Data Comparing Sirolimus-Eluting Stents with Bare-Metal Stents. N Engl J Med. 2007;356(10):989-97
- ↑ Maisel WH. Unanswered Questions - Drug-Eluting Stents and the Risk of Late Thrombosis. N Eng J Med 2007 356;10:981-984
- ↑ Boden WE, O'Rourke RA, Teo KK, et al. Optimal Medical Therapy with or without PCI for Stable Coronary Disease 10.1056/NEJMoa070829 accessed 26.03.07 registration may be required
- ↑ Cayla G, Hulot JS, O'Connor SA, Pathak A, Scott SA, Gruel Y, Silvain J, Vignalou JB, Huerre Y, de la Briolle A, Allanic F, Beygui F, Barthélémy O, Montalescot G, Collet JP. Clinical, angiographic, and genetic factors associated with early coronary stent thrombosis. JAMA : the journal of the American Medical Association. 2011 Oct 26; 306(16):1765-74.(Link to article – subscription may be required.)
- ↑ van Werkum JW, Heestermans AA, Zomer AC, Kelder JC, Suttorp MJ, Rensing BJ, Koolen JJ, Brueren BR, Dambrink JH, Hautvast RW, Verheugt FW, ten Berg JM. Predictors of coronary stent thrombosis: the Dutch Stent Thrombosis Registry. Journal of the American College of Cardiology. 2009 Apr 21; 53(16):1399-409.(Link to article – subscription may be required.)
- ↑ Iakovou I, Schmidt T, Bonizzoni E, Ge L, Sangiorgi GM, Stankovic G, Airoldi F, Chieffo A, Montorfano M, Carlino M, Michev I, Corvaja N, Briguori C, Gerckens U, Grube E, Colombo A. Incidence, predictors, and outcome of thrombosis after successful implantation of drug-eluting stents. JAMA : the journal of the American Medical Association. 2005 May 4; 293(17):2126-30.(Link to article – subscription may be required.)
- ↑ Daemen J, Wenaweser P, Tsuchida K, Abrecht L, Vaina S, Morger C, Kukreja N, Jüni P, Sianos G, Hellige G, van Domburg RT, Hess OM, Boersma E, Meier B, Windecker S, Serruys PW. Early and late coronary stent thrombosis of sirolimus-eluting and paclitaxel-eluting stents in routine clinical practice: data from a large two-institutional cohort study. Lancet. 2007 Feb 24; 369(9562):667-78.(Link to article – subscription may be required.)