Taken in isolation, some of the new, minimally-invasive procedures are less expensive by far, when analyzed on a procedure-by-procedure basis, than previous significant surgical interventions, as demonstrated below:
Estimated duration of 'cure'
PCI (percutaneous coronary intervention
Based on the above analysis, it would appear to be clear that a PCI is more cost-effective than CABG procedures. This may not be true when all costs are considered, however. The logic of comparison needs to include additional factors than the 'cure' period and the direct procedural costs.
CABG cost discussion
CABG can vary from a simple mammary artery, single bypass to a 3- to 5-vessel bypass graft operation with the use of saphenous vein grafts from the leg. Many of the single-artery bypass operations have been overtaken by PCI in the past few years, as the need to 'open' single vessels has been taken in most areas of medical practice. There are some single-artery bypass operations which are necessary for better patient outcomes, however. These include:
Left main disease: the patient outcomes for left main disease are better for mammary artery bypass operations, whereas there are complications which can occur with PCI
Ostial disease: there is a danger that the placement of a stent (or a balloon in the case of POBA -- plain, old balloon angioplasty) will be compromised if not done exactly in ostial lesions. These represent approximately 5% of all lesions seen under angiography.
CTO, or Chronic Total Occlusions: These occur in about 35% of patients diagnosed with significant cardiac arterial lesions. Interventionalists are able to penetrate about 50% of these lesions with normal guidewires, "CTO" guidewires, such as the Asahi wire, or with specific devices which have been developed to penetrate CTO's. That leaves about 20% of patients with complete blockage of one or more arteries; some of those patients are treated medically, as they may be too old or too sick to undergo CABG. In some cases, the collateralization of the arteries is such that the patient can continue without major problems without undergoing a subsequent CABG operation.
Concomitant valvular disease which may require open-chest surgery. In the U.S., there are about 62,000 aortic valve replacement surgeries performed yearly, of which there are an estimated 20-25,000 patients who also receive CABG at the same time. The same is true for CHF patients who undergo mitral valve replacement or repair surgery. It is not uncommon for the cardiac surgeon to perform a "drive-by" CABG as a part of mitral valve repair or replacement.
Recent improvements in less-invasive or 'minimally' invasive CABG have given the cardiac surgeon reasonable tools to be able to take back some patients who were earlier lost to PCI procedures. These include mini-throacotamies, which cut only a part of the sternum, and can heal faster, to sub-apical surgery, in which the patient's sternum is not cut or broken, and the surgeon operates underneath the patient's sternum to approach the heart from the apex.
Mini-thoracotomy (Medtronic, 2008)
The costs of CABG include significant personnel and institutional charges, while the materials used are relatively minor in the overall cost picture. In a CABG procedure costing $25,000 to $40,000, the primary costs include:
Surgeon, anesthesiologist and medical staff during the operation
Hospital charges, with a stay of about 3-4 days, of which some portion is in the CICU, and some portion in normal in-patient beds, including patient prep room
Some medical devices, costing less than $1,000 (surgical prep tools, mostly)
Operating room charges, which are substantially more expensive than, for example, cath lab charges
Thus in comparing PCI with CABG procedures, the complicating factors can make direct comparison difficult. Patients who undergo CABG tend to have longer improvement times than patients undergoing PCI, but the results can vary significantly from patient to patient. The most common problems with CABG patients with multi-vessel grafts are infection, particularly in the long saphenous-vein extraction portion of the surgery, and stenosis at the anastomatic site. Stenosis occurs in 20-30% of the patients within the first year after surgery, and is generally related to poor technique and/or poor circulation within the media and adventitia of the grafted vessel (which can be pinched off or have poor circulation to begin with). In many cases, this stenotic response can be dealt with using a PCI approach, generally with POBA, and sometimes with a non-DES stent.
If patients' CABG procedures do not encounter these side-effects, the patient can generally enjoy reduced or eliminated angina pain for five to seven years, at which point a CABG procedures may need to be performed again. In the patient who has developed additional complications, a new CABG procedure may not be indicated; in many such cases, CABG patients will then undergo PCI. If one assumes that the patient who first undergoes CABG is 55 years old and lives another 20 years, the possible costs of cardiac treatment with a beginning CABG could be as follows:
If, on the other hand, the patient undergoes a CABG surgery, lives 20 years, and receives a timely follow-up PCI over the period, the total costs would be as follows:
Primary Coronary Intervention
This section will deal with two types of PCI: post-AMI author acute angioplasty and PCI are related to relieving of angina symptoms and their sequelae.
Post-AMI author angioplasty
The post-AMI author direct procedure involves bringing the patient directly from the emergency room to a waiting cath lab which is equipped to perform both angiography and an angioplasty intervention. This is generally the case in hospitals or cardiac specialty centers with a high volume of patients and the ability to attract physicians and staff which are willing to work a 24-hour schedule (which adds to the cost of the procedure). In this case, the literature is clear that patient outcomes significantly benefit from rapid PCI, with overall reductions in morbidity and mortality as compared to medical (i.e. drug) treatment. Since there is no surgical alternative here, a direct cost comparison need not be done.
The reasons why PCI is so effective have to do with the nature of the arterial blockage. An AMI author is generally caused by a thrombus which is released somewhere in the body and finds its way to a major cardiac artery, causing the artery to completely block off circulation to a major portion of the heart muscle.
While drug treatment, primarily TpA, can help to 'dissolve' the clot, there are dangers in using the drugs without subsequent follow-up PCI. The first danger is that the patient may be susceptible to bleeding elsewhere in the body. A major concern is hemorrhagic stroke, which occurs more than 50,000 times in the U.S. per year. This concern has kept the number of patients receiving TpA to less than 10%, despite clear clinical evidence that additional use of TpA could save lives (particularly where there is no primary PCI available).
The second issue with clot-busting drugs is that they may take too long to be effective. That is because the age of the clot, and therefore its composition, may affect how quickly the clot can be reduced by the drug. This is particularly true of the AMI author patient, where there is little circulation at the infarction location (because flow has been inhibited or stopped). If the clot has formed elsewhere in the body, it could be older, and therefore harder to affect with TpA.
A third issue is that clot-busting drugs only affect the thrombi that may be circulating in the bloodstream. They do not directly affect the underlying lesion which may be causing the cardiac blockage.
IVUS and angiography vision of a thrombus pre- and post-stenting (Chen, 2008)
In the above image, one notices that the AMI author patient has a large thrombus which is blocked by soft plaque in image a. Image B. is the same vessel at the lesion site, demonstrating a large amount of soft plaque and thrombus at the vascular blockage (this is an IVUS, or intravascular ultrasound, image). The emplacement of a stent (Image D) both pushes the thrombus into the vessel walls (where it is dissolved) and clears any lesion which may be present. The stent's struts are visible on D. due to the reflection of ultrasound, while image C. demonstrates an open vessel with removal of the blockage at the lesion site.
In a typical
The other major use of angioplasty is following a diagnosis using angiography, in which case the doctor finds a significant reduction in circulatory ability which has been evinced through one of several non-invasive diagnostic procedures, such as a thallium scan, a cardiac stress test with subsequent echocardiography, a 'chemical stress test,' which uses adenosine in order to induce a higher heart rate, or patient symptoms (particularly angina with exercise).
In all these cases, the angiographer is also licensed to perform angioplasty, and the "occulo-stenotic response" is a key factor in a diagnostician/therapeutic MD's decision to proceed. Although there are a series of…