UK Cardiac Audit Reveals Some Good, Some ‘Appalling’ Trends in PCI

Operators in the United Kingdom outpace most of the world in the use of radial access and imaging-guided PCI, but also are struggling to lower the call-to-balloon (C2B) times of their STEMI patients, according to new data from the British Cardiovascular Intervention Society (BCIS)’s annual national audit.

“Call-to-balloon times are pretty appalling,” said Mamas A. Mamas, BMBCh, DPhil (Keele University, Stoke-on-Trent, England), who presented the data last week at the BCIS Advanced Cardiovascular Intervention 2024 meeting held in London.

“Only about a third of patients achieve a call-to-balloon time of 150 minutes. You’ve got about 70% who go to a non-heart attack center and miss the time line,” he told TCTMD. “To my mind, this should be a serious national discussion around whether we should be offering thrombolysis in these patients.”

Part of the problem stems from the emergency services tier structure in the UK, which can leave patients stranded for hours at a non-PCI center awaiting transfer, said Mamas. Others are stranded in the ambulance waiting for offloading into overcrowded hospitals, taking the ambulances out of service for hours.

“There are a number of questions that need to be part of our national conversation,” said Mamas. “Why are patients being taken to local centers rather than PCI-capable centers? Is it a problem of diagnosis? Additionally, can thrombolysis be delivered in the emergency department? Because let’s not forget that many have lost the ability to deliver it. Only a small number of thrombolysis for STEMI were undertaken in the entire country last year. The huge expertise that we had in delivering thrombolysis 20 years ago has been lost.”

In the United States and elsewhere, fibrinolytic-based strategies came to the forefront in the early days of the COVID-19 pandemic as a way of easing patient traffic in overwhelmed hospital systems. But some have argued that it’s an excuse for systematic failures.

“In my interventional cardiology practice, it’s not usual that patients are waiting for 4 or 5 hours after being diagnosed with a STEMI in one of our regional units to be transferred to us for primary PCI,” Mamas noted. “Are those patients better off having thrombolysis? My answer would be yes. Many would see it as a retrograde step, and it is—but if you are unable to deliver primary PCI in a timely manner, you have to act retrogradely for patient safety.”

Wide Variability in Clinical Practice

The national audit also showed wide variability in practice across UK centers in IVUS or OCT guidance, used in an average of about 25% for ACS cases and rates above 70% in left main disease.

“Some centers use imaging in close to 100% of their left main cases, whereas other centers use it in less than 50% of cases,” Mamas noted, adding that the UK may be second only to Asia when it comes to intravascular imaging in PCI.

Despite RCTs and observational reports supporting the addition of IVUS to optimize PCI, its use is known to be generally far lower in the US, with one recent study showing just 5.6% of all PCIs in Medicare patients are performed with IVUS guidance. Physician preference and hospital culture have been shown to be influential factors.

Another important finding from the report is that use of drug-eluting balloons (DCBs) has skyrocketed from 0.2% of ACS PCIs nationally in 2018/2019 to 7.2% in 2023, and from 1% of restenosis cases to just shy of 30% during the same period. The European Society of Cardiology (ESC) guidelines give DCB use in in-stent restenosis of DES or BMS a class IA indication.

Other findings from the report include:

• The average annual number of PCIs performed by an operator in the UK is 117
• Radial access is used in approximately 94% of all PCI cases
• Seventy percent of all PCIs are undertaken for ACS
• Unprotected left main PCI has steadily increased, representing 4.5% of PCI procedures
• Just under 40% of all centers have on-site cardiac surgery
• There is wide variation in PCI to CABG ratios, ranging from 10:1 to 100:1
• Chronic total occlusions represent about 11% of elective PCI cases in England and Wales, but reached as high as 30% of cases at one center
• Intra-aortic balloon pumps are used in 15% of shock cases, also with significant national variation
• Prasugrel is being used in only about 3% of NSTEMI cases despite an ESC class IIA (level of evidence B) recommendation over ticagrelor

The UK data show that while cutting balloons are the most common device used in calcium management, a crossover has occurred in recent years from rotational atherectomy to lithotripsy. While rotational atherectomy was used in 1,600 cases nationally, lithotripsy was used in 2,500.

Asked what could be driving that trend, Mamas told TCTMD that there are several explanations.

“Ease of use is top of mind, but I also think that it might reflect a better appreciation of calcium,” he said. “I think people are increasingly aware of the risk of poor outcome associated with calcium post-PCI. A second thing that is driving this is increasing adoption of intravascular imaging. It has changed how we appreciate calcium and helps identify cases that would benefit from more advanced algorithms of calcium management.”