Patients with coronary artery disease (CAD) who don’t respond to medical therapy alone are often treated with angioplasty and stent placement or coronary artery bypass graft (CABG) surgery (also known as open heart surgery). These procedures restore and improve blood flow to the heart, thereby alleviating the patient’s symptoms and preventing (or treating) heart failure. However, not all patients with symptoms of CAD are able to undergo surgery. Some patients have clinical conditions that put them at high risk for complications or prolonged recovery after these procedures.

A patient who is not a candidate for bypass surgery may be a candidate for a coronary revascularization in higher risk and indicated patients (CHIPs) procedure. These are minimally invasive procedures that use angioplasty and stents to achieve complete coronary revascularization without surgery. In some cases, special devices may be used to support the heart during the procedure and to prevent complications.

Who Is a Candidate for Chip?

CHIP is intended for symptomatic patients with multi-vessel coronary artery disease who are at high risk for complications with CABG. These patients may be elderly and/or have preexisting medical conditions, such as uncontrolled diabetes, or kidney, lung or liver disease, that put them at high risk for complications after surgery or complications related to anesthesia. Some patients who have already undergone CABG surgery and are not candidates for redo bypass are also eligible for CHIP.

How Does Chip Work?

A CHIP intervention starts with diagnostic angiography during which an interventional cardiologist inserts a catheter from the wrist or the groin and uses it to inject contrast into the coronary circulation. This allows the cardiologist to take pictures of the coronary blood supply and identify critical blockages. This series of images, called a coronary angiogram, allows the interventionalist to plan the angioplasty (ballooning) and stenting procedures.

The stent is a wire mesh tube that is left inside the artery to keep it open after balloon dilation. If the patient’s arteries contain an extensive amount of calcium, or plaque, the physician might also utilize special devices to shave away some of the calcium to make room for the stent.

CHIP intervention differs from ‘routine angioplasty’ in that the coronary anatomy is complex and may require the use of multiple stents. Some arteries may be completely blocked (known as chronic total occlusion, or CTO), necessitating the use of specialized tools to cross the blockage. Patients who have heart failure may need the use of a circulatory support device (heart pump) to keep the blood pressure and heart rate stable during CHIP.

Most patients are able to sit up and to walk within a few hours of the procedure, and often go home the next morning.

How Does Chip Differ From Other Treatments for Cad?

Historically, angioplasty and stents have been used for people with few and relatively straightforward blockages. Surgery was considered the only option to treat extensive and/or complex disease. CHIP offers the benefits of both without requiring the patient to undergo open heart surgery.

Sometimes, a CHIP procedure may also be used in addition to CAGB surgery, whereby some of the revascularization is achieved through surgery, and any residual arterial stenosis (narrowing) or blockages are addressed using CHIP. This allows a patient with very complicated anatomy to have complete revascularization with the least amount of risk.

What Are the Benefits of Chip?

With CHIP, patients who need revascularization get the improvement in blood flow they need to recover their cardiovascular function and improve their symptoms of angina or congestive heart failure without having to undergo a procedure that might be life threatening. Most patients who undergo a CHIP procedure experience a marked improvement in their quality of life and are able to resume their usual activities without a prolonged interruption.

Risk and Side Effects

While angioplasty and stent placement is a less invasive way to expand narrowed or clogged arteries than traditional bypass surgery, but there are still risks involved. Some of the possible side effects include:

  • Bleeding, bruising or infection at the site where the catheter was inserted
  • Rupture of the coronary artery
  • Abnormal heart rhythms
  • Chest pain or discomfort
  • Allergic reaction to contrast dye
  • Kidney damage from contrast dye
  • Heart attack during or after the procedure
  • Stroke after the procedure

Patients who are planning to undergo CHIP should have a detailed discussion with their interventional cardiologist about these and other risk factors.

The heart and vascular specialists affiliated with Memorial Herman have a longstanding history of performing complex surgical and interventional heart procedures. At Memorial Hermann, we have one of the highest volumes of coronary procedures in the Greater Houston area, and our CHIP program treats patients from across Southeast Texas and beyond.

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