Survival of the fittest. It applies in the wild, and it applies in the business world. The companies that survive and thrive must possess something that others don't.

Pretty much every company will say that it has competitive advantages over rivals. Although those advantages aren't always all they're cracked up to be, there are some businesses and stocks that do enjoy strong competitive advantages.

Healthcare is a sector where the differences between the truly great businesses and the mediocre ones can be especially pronounced. Three healthcare stocks that I think have a killer advantage right now are Abiomed (NASDAQ: ABMD), ShockWave Medical (NASDAQ: SWAV), and Vertex Pharmaceuticals (NASDAQ: VRTX).

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1. Abiomed

One way to dominate a market is to invent a new one. That's basically what Abiomed did in heart recovery with its Impella heart pump. Impella protects, supports, and recovers heart muscle while enabling high-risk percutaneous coronary interventions (PCIs) -- formerly known as angioplasty with a stent.

Other companies make heart pumps. But Abiomed's Impella is the smallest on the market. More importantly, it's the only heart pump approved by the FDA for high-risk PCI. Even if a rival launched a product to compete against Abiomed, it would have a tough time outmatching the impressive track record for Impella, which has been used to treat more than 100,000 patients across the world.

Abiomed's biggest "enemy" right now appears to be the FDA itself. The agency issued a letter in February about the Impella RP heart pump that confused healthcare providers. Although the FDA clarified matters with a follow-up letter in May that confirmed that the device was safe and effective, the damage had already been done. Abiomed's revenue growth slowed in both the first and second quarters of 2019.

The fundamentals for the company remain strong, though. Abiomed had penetrated only around 11% of its current addressable market of $6 billion as of the start of 2019. The company expects to capture this entire market over time and grow even more by adding more indications for Impella.

2. ShockWave Medical

Abiomed owns a $95.8 million stake in ShockWave Medical. Like Abiomed, ShockWave is a medical device company that invented the market that it dominates.

Lithotripsy -- the use of ultrasound shock waves to break up small particles in the body -- has been used for decades to break up kidney stones. ShockWave saw an opportunity to use the technology to unclog arteries. The company won U.S. and regulatory approvals last year for its intravascular lithotripsy (IVL) system used in dissolving calcified plaque in patients with peripheral vascular, coronary vascular, and heart valve disease.